A free host of web pages. Formerly an independent host, currently operated by Yahoo!.
Geocities is one of the oldest free web hosts, and has been one of the best of them throughout the history of the World Wide Web. Currently, they provide enough web space for individual's page (15 megs - my own page, that is not there and has some serious amount of content, takes a lot less... I have a small roleplaying-related page there, though =), enough bandwidth without too many limitations (just don't post your link to Slashdot and you're fine =), and (until recently) also a FTP upload thing (that has since been made a premium service - and the premium package also has stuff like PHP, subdomains and passwords and other stuff that all respectable web hosts do =). Also, the ad banners they add to the sites are not too annoying (at least from my experience - all I get in Mozilla is a small floating ad box that says "undefined". =)
Also, earlier Geocities sites were set in "neighborhoods" and got a "house number", so people's URLs looked like http://www.geocities.com/Neighborhood/XXXX/YYYY/... After Yahoo! came about, numerous cool things happened - the disk quotas got WAY up (shortly before the move they only gave 2 megabytes of space!) and URLs were made shorter and more logical - http://www.geocities.com/membername/.
For most personal purposes, it's enough for starters. =)
UPDATE: GeoCities was shut down on October 26, 2009. The Japanese version remains active.