depends on what you are going to do with it.
I'm kind of partial to wikidot.com because it is free for a basic site (five, actually) and the advertising is minimal. Since you have signed up for a wikidot account, you can create up to five wikis right now. Just go to 'My Account' next to your name, and then go into 'My Sites'.
Other options: If you want to continue to post new material, then you may be better off with one of the free blogs (wordpress.com, blogger.com, typepad, livejournal, etc.)
If you want a website where you can post your own material, and be a bit more flexible than a wiki or blog, then you can go to the freeweb.com or something like that. "Flexible" in this context means more work for you… blogs and wikis do a lot of the back-end legwork for you. Just be aware that they are ad supported, so you are going to see a lot of ads on you pages.
Beyond that, there are about a thousand web hosting companies that (for a fee) will let you do whatever you want, without ads.