Editor's note: This post is part of the Overheard on CNN.com series, a regular feature that examines interesting comments and thought-provoking conversations posted by the community.

One story about Mitt Romney's estimation that he has an effective tax rate of about 15% drew more than 13,000 comments. New Jersey Gov. Chris Christie, a supporter, has called for Romney to release his tax returns, and the South Carolina GOP race is heating up. Romney mentioned that he made about $375,000 in speaker fees, which he called "not very much." Commenters debated whether current tax policies are fair, and they also discussed Romney's views about perceived income disparities.

Mitt Romney's tricky taxes

Romney's money comes from mostly investment-related sources, so his tax rates are somewhat lower than the rate on wages. Fortune's Dan Primack says such lower tax rates (like capital gains rates for profits on investments) are intended to reward taking on the risk of investment and being in business, but also suggests there are loopholes that give some people tax breaks without assuming enough risk to justify it. Readers debated the finer points of taxation policy.

black743: "This isn't a loophole. You invest, you pay 15% on the capital gains. What's so hard to understand about that? He doesn't get a paycheck anymore, he's retired. This is a 15% tax on capital gains of investments. Why can't you people get that through your heads? I would love to see one of you suddenly come into wealth. I'm sure you would just give 35% to the IRS out of the goodness of your hearts, right? I'm so sick of this wealth envy in this country. If we keep raising capital gains taxes on investments, then it's quite easy for folks to just invest in other countries and leave America high and dry."

terre08: "You are wrong. Almost all of his income from Bain was taxed at 15% due to lax regulations when it comes to equity firms. He has a 'pension' as well from Bain where he pays 15% as well for the same reason. It is obviously not called a pension."

The following reader argued capital gains taxes could be raised, since the rates have been higher in the past. (Some are proposing to raise these rates in the future, while others seek to lower them or eliminate the tax entirely.)

Algeria Touchshriek: "Bear in mind that capital gains taxes have simply never been so low. During the Republican idol Ronnie Reagan's era, they were 28%. This little Bush/think-tank experiment has clearly failed, and it's time to bump the capital gains tax rate back up."

One poster said this whole situation was hardly breaking news.

Latch2010: "Wait, you're telling me that the 1% have tax loopholes they use to escape paying their fair share, all the while pointing at the 35% number and braying 'See?! I pay huge taxes!' Colour me shocked, surprised, and clutching for my pearls."

Several commenters suggested that maybe a flat tax is in order. There were also several who were opposed to the idea.

David R. Priest: "Let's put a 15% flat tax with no deductions except charitable, children and a generous personal exemption. This would be fair to everyone. If Mr. Romney paid all of his taxes and broke no laws, there is no issue here."

groksmith: "Brilliant! Shift the entire tax burden from those who can actually pay (the rich and middle class) to those who can't (the poor). Ya, that's not going to have any lasting repercussions for the country. Crackerjack Box economics at its best."

There were a lot of commenters who noted that Romney isn't breaking any laws and thought people were making too big of a deal about the situation. Others wrote in to say that they want to know more about this person who wants to be president.

Wis09: "I'm all for closing loopholes. But Romney is paying taxes LEGALLY based on an existing tax code that he had no part in creating. Why are you even making this a discussion?"

groksmith: "Right...because we can't discuss laws that need to be changed or amended or even created for exactly what reason? How else can you identify and close loopholes if you do not shed some light on them? Come on, it's really not that hard to follow along, is it?"

ldsmom: "But that isn't what you are doing, you are discussing Romney and trying to make him out to be something he isn't just because he is wealthy. If you wanted to change the Tax Code you would have voted into office men/women who would do that, but you continue to vote in the same rich powerful people and then try to blame someone like Romney for something they never did."

RKen: "I'm not sure what rock you've been under, but we are 'even making this a discussion' because this currently a hot topic in the tax reform debate. And Mitt, whether he likes it or not, through the spotlight shed on him in being a front-runner is going to become a well-known example of why people disagree with the regressive aspects of our tax system. Whether you agree with that or not, I think it's pretty obvious why it's being discussed."

nzgrrj: "The reason this is significant is because he has come out and said the system shouldn't be changed and should continue to reward him. Romney hasn't "worked" since 1999 – He is a trust fund kid. I don't begrudge someone that gets wealthy CREATING something (e.g. Bill Gates). Excuse my contempt for a man that has never in his life experienced adversity or had been knocked down then having the mantle of knowledge to go on preaching about hard work and pulling oneself up."

Some discussed why Romney might not want to share his tax returns. Some speculated there might be something to hide, while others said he has a right to financial privacy.

macbll: "There's a possibility that Romney is paying less than 15% if Bain funneled profits through off-shore entities. Also, there is the possibility that Romney is hesitant to release his tax forms because he probably gave a lot of money to the Mormon Church and that's going to deepen the evangelical audience's suspicions about him, ie promoting a "non-Christian religion."

nosense: "Or there's the possibility that he is hesitant to release his returns because he values his privacy like most other people I know. I don't have anything to hide on my tax return, but I value keeping it private myself. Why do I need to know what's on his personal tax return to decide whether or not to vote for him? If there's any concern about them, the IRS can audit them, not us. Furthermore, his accountants, who I'm sure have a stake in making sure their work is done according to law, also have looked at them."

The most-liked Fortune comment was about Romney's speaking fees, which are another component to the candidate's net worth.

earledecker: "By Romney's own admission, he pays 15% in federal taxes. He also says 'I don't make much from my public speaking.' Last year he made $374,000 from his speaking engagements. That is nearly 10 times the income of the average American. Romney is clearly out of touch with the average American. On the other hand, President Obama paid his Federal taxes at a 33% tax rate. Personally I can relate to President Obama and his tax rate. Now you decide which is fair."

Readers had quite a bit to say about the speaking fees issue.

Romney's speech income big money for most

Romney earned $374,327.62 in speaking fees between February 2010 and February 2011, according to documents the candidate filed with the Federal Election Commission in October of last year. The first edition of his book was published in March 2010. Some outrage was expressed at the "not very much" remark.

sonny chapman: "It's like when Bush Sr. was amazed at the price scanner in a grocery store. Or, when Marie Antoinette told the rioters without bread to 'eat cake.' Different planets than the peasants."

But maybe it doesn't matter, as this commenter argued.

JLFuller: "More power to him. Even if $360,000 is not much to him but it is to me, more power to him! I don't give a rat's behind if he makes more in a month than I will make in my life, I will vote for him for what he can do for me and my country. How much he makes or has in assets is none of anyone's business."

Perhaps Romney spoke a bit hastily?

Nobodies Pon: "Whoever paid Romney to speak got ripped off. That guy stumbles over his words most of the time. He has a good radio voice good for sound bites. All that hot air he spits out he should start a hot air balloon ride business."

Some were also baffled by Romney's remark about his speaking fees.

Romney reveals he pays about 15% in taxes

mrphil108: "It's not the 15% that bothers me, as that was he's supposed to pay for capital gains (and I'm a liberal so, yes, some of us do understand the tax code). It's that he refers to $300,000+ as 'a little bit of money.' Just goes to show how out of touch he is about working-class Americans."

And then, some interesting conversations began about wealth-building strategies.

XoriusM: "I pay 36% in taxes. I make less than $100k per year. I'm young and I have no write-offs. I'm tired of carrying the nation on my back while people like Romney don't put in their fair share.

XoriusM: "My federal taxes aren't 36%, they are around the 20s. The rest go to Social Security, state taxes and Medicare. I made $81,000 last year. I payed $29,000 in taxes."

MiddleMomDoc: "Welcome to the middle class. You are paying for irresponsibility and greed of all sorts."

RJM: "So you paid ($29,000) in taxes. How much do you think Romney paid? I'm guessing well over six figures. So who's carrying who?"

dredd57: "If you're paying that much, you better fire your tax preparer and get a new one."

Maiaw: "You are young. Start investing in stock or purchase a house. You can be a millionaire when you retire if you plan now. If you are investing in your 401K, most is likely going into the stock market. Your dividends or any gains over a year will likely be taxed at 15%. (Romney) is being taxed on his gains just like you will when you retire! If you pull out your stocks and gains held less than a year, then it will be taxed more! He is following the tax law. Get educated and get your share before the tax law changes. Don't blame others for planning ahead and making the most of their money. I'm sure (Newt) Gingrich and Obama probably are doing the same thing but just aren't getting as much money out of their investment as Romney. I also agree with dredd57, paying 36% in taxes is way too much. Get some assistance! My husband and I make $175K/year and pay just 20% in income tax."

One commenter said Romney's 15% number is open to interpretation.

Foxtrot22: "Romney thinks he 'probably' pays about 15% in taxes! Does anyone honestly believe this self-proclaimed financial wizard who is so very reluctant to release his tax returns doesn't know EXACTLY how much he pays in taxes!? And does his damnedest to pay as little as possible thanks to the Bush tax cuts and the many other welfare for the wealthy features built into the tax codes! And who pays taxes in Romney's stead? The middle class, of course."

bptsj: "Don't we all try to pay as little as possible? Also, if your income is from many types of investments it is not easy to know what your effective rate was. Maybe last year it was 15% maybe this year it will be 17% ... Also, it doesn't help that every year the tax laws change ..."

Some commenters were wondering about President Obama's tax returns. If you want, you can indeed download them from the official White House website, as the commenter below notes.

StoneTools: "Have you seen Obama's taxes yet?"

want2believe: "They are available for all to see on the White House website. You clearly do not know the power of Google."

This person was longing for the era of former President Clinton, but others were quick to remind them of other things to consider.

useyourhead: "It's amazing how Clinton era taxes were well-balanced. Why can't we just go back to then? 20% capital gains taxes, 39.6% for the upper bracket. It's not rocket science people, it is common sense."

CincyFin: "At least you make a rational argument."

Masse: "Well, we do have the long-term, more serious problem that we are competing with a world market that's happy to make $1/hour or $8/hour as a engineer PhD."

After reading all these thoughts, and reflecting on your own experiences with taxes, what do you think? Share your opinion in the comments area below and in the latest stories on CNN.com. Or sound off on video via CNN iReport.

Compiled by the CNN.com moderation staff. Some comments edited for length or clarity.