After all these years, you guys still never cease to amaze me.

Was I a little rough? Yes. Did I bash the mutual fund industry for sticking it to us? Sure. Did I expect a little hate mail? Of course.

Are you feeling a little lost?
Don't worry -- here's a quick summary. In a recent column, I proposed an experiment: a bogus mutual fund made up of just three stocks, each bought in January 1990 and sold exactly 10 years later.

For my fund, I chose these three familiar large-cap techs, but any number of former highfliers could have done the trick:

The idea wasn't to show how a $10,000 investment could have ballooned to more than $3.3 million in 10 short years, which it did -- but rather, that there was a cost involved.

In those 10 years, you'd have paid your mutual fund manager nearly $130,000 in fees and surrendered nearly $600,000 in lost profits (money not earned on those fees). So, instead of $3.3 million, you'd be sitting on a lot less.

So, you hate me, right?
Of course you do, but not for the reason I expected. I thought you'd take the funds' side and point out that nobody could have found Microsoft, Dell, and Oracle in 1990, much less timed the market so perfectly.

I thought you'd tell me that my $730,000 blood money was a gross exaggeration. Just wait until you hear what most of you really said. For more details on my little experiment, check out "Don't Invest Another Penny." But please come back, because this is where it gets good.

You got worked like a chump!
Or so you told me. Apparently, you're OK with my comparing the U.S. fund industry to an IRS on steroids. Most of you took me to task for understating the case -- for trivializing the real cost to you as an investor, at least on a percentage basis.

And you're right. John Bogle -- the founder of Vanguard Funds, who visited us recently here at Fool HQ -- makes the case bluntly. In his book The Battle for the Soul of Capitalism, Bogle shows how you don't need blowout returns (like in my superstock '90s example) to make the case against most mutual funds ... you need time. Here's why.

Beware the "tyranny of compounding"
As it turns out, in my "super fund" example, financial "intermediation" costs would have eaten up just 22% of your total returns ($730,000 out of $3.3 million). That sounded like a lot to me, but apparently not to Bogle -- and not to some of you, either. In fact, for most of us, it will likely be much worse.

For one thing, we won't be making 30,000% every 10 years, like in my example. That's because for every Corning (NYSE: GLW) that your manager rides for a 600% bounce off the bottom in October 2002, he'll clutch a CMGI -- now mysteriously known as ModusLink (Nasdaq: MLNK) -- for a 90% plunge. If we're lucky, our guy will stick to the usual tigers like Johnson & Johnson (NYSE: JNJ), along with everybody else. Continued...