First, a key for how hard-core each site is: 
* Makes Hilary Duff look naughty
* * It's nothing you wouldn't see on Skinemax
* * * Might make porn newbies a little uncomfortable
* * * * Might make R. Kelly a little uncomfortable
* * * * * Scary, and not in a good way
COST: Free

We know you're no stranger to blogs, but erotic blogs — that's probably another story. Gracie writes about her own sexcapades, and while there's no plot, there is plenty of action — some of it questionable. (She's into pain, choking games, and reclaiming the C word.) At least you won't have to flip through those Harlequin books for the good parts anymore.
COST: 8 cents/minute

As the name suggests, this one's for us. Endorsed by postfem mag Bust, this site presents a mind-boggling 65,000 movies. All can be viewed full-screen, in good quality. The best we saw was a classic from '70s porn auteur Roberta Findlay — there's just something about a burly, hairy man in massive aviators and head-to-toe Wrangler.... Sorry — TMI?
COST: $21.95/month

Touted as the "thinking person's adult site," this one is basically vintage photos — 47,000 mostly black-and-white images of tasteful nudity and sex from the past 100 years. No plastic tits — it's erotica for real people. If porn were baseball, this would be first base.
COST: $29.95/month

Jen, a 30-something wife and mother and, apparently, an exhibitionist, offers two live webcam shows a week, plus three 24/7 webcams placed around her house. Not digging Jen's dirty tricks? Write in and tell her what you'd rather watch her do — if she can oblige, she will. A word of caution: There is footage of her balding, salt-and-pepper-hair husband going down on her. Not arousing.
COST: Free

This site makes Nora Roberts look like Dr. Seuss. With hundreds of free erotic stories, there's something for every fetish (alien sex, anyone?). Think you can do better? Let your inner Jenna Jameson run wild and submit your own typed porn. Bonus: If you're tired of "BrickBreaker," click on free games and play "XXXMan," where a not-so-coy Ms. Pac Man type chomps up tiny penises instead of ghosts. Talk about a man-eater!
HOW HARD-CORE: * * * *
COST: $29.90/first month; $24.90/month thereafter

Dominatrix fantasies? The how-tos are all here. Use the pictures for tips on how to hold the whip, where exactly to place the heel of your boot, and how to best punish him for being very naughty. (Step one: Make him address you as "Miss All-Knowing Queen of the Galaxy.") And if you've got a shoe fetish, you'd better sit down for this one. The footwear is fabulous.
COST: Free

One-stop shopping for porn geeks. As if 15,000 reviews of 48 varieties of porn (and space for you to submit your own critiques) weren't enough to keep you busy, this site also has interviews and podcasts with porn stars and directors, a weekly newsletter, and sale alerts. More for guiding your rental fun than providing it, it's way better than the back room at your local video store. Plus, half the pleasure comes from scrolling through the lists for yuk-yuk titles. Our favorite? The Da Vinci Load.
COST: From $29.95/month

Call us shameless voyeurs, but these videos of women caught in the (mainly solo) act made us want to grab our own battery-powered devices. Artfully shot using natural-looking participants, the site is a multimedia homage to the beauty and power of female orgasm. But a women's-studies dissertation it is not: The clips, divided into "solo" and "friend" categories, are explicit and hot. "O" yeah.
HOW HARD-CORE: * * * * *
COST: $29.75/month

Hard-core video action divided into a dazzling array of special-interest categories (,, If "kink" conjures up quirky, vaguely racy images for you, prepare for a shock to the you-know-what. We found the clit clamps, strap-ons, and anal insertibles a bit intimidating, but enthusiasts rave about the site's "respectful and positive" approach to BDSM play. We agree, master.
COST: Free to enter; $20/month for VIP membership

Second Life fanatics will recognize this setup, wherein you go through a virtual world with a character based loosely on yourself, to interact — and we do mean interact — with other avatars. Just note: Your cheap thrills will cost you. It's free to troll, but only paying VIPs can drop their clothes. Once again, art imitates life.

You should also check out:

Marie Claire's official guide to Fifty Shades of Grey

7 Reasons to Have More Sex

What Do You Think?