That's it. I use it as my homepage instead of google (because it takes google results), and every now and then a message will pop up above your search saying:
"Congratulations! You have won ____ (usually 1, 2, 5, 10, or on mega days 20, 50, and 100) Swagbucks! They have been automatically added to your account."
Then, after searching regularly and saving up for a while, you can use the Swagbucks to redeem something cool for free from the store. So far I've snagged myself a $5 Starbucks (a coffee place) gift card, a $5 amazon gift card, and a few sweepstakes entries, and I've only been signed up since the end of January!
Its simple, useful, and gets you some free stuff! Overall a great site. And also, if you plan to purchase online, do it though the rebate store, theyre partnered with stores and you'll get a swagbuck for every $5 you spend! They also usually have savings deals and printable coupons!
Later on they've announced a trade video games system (and play them, too) to win swagbucks. Every now and again they'll release a swagcode that you can put in your profile redemption box for a few more free swagbucks!
Anyway, if you wanna sign up, here's the link:
http://swagbucks.com/?cmd=sb-register&rb=292936It's completely legitimate and completely awesome.