Everyone who used the Internet in the 1990s remembers the ubiquity of "AOL Keywords." They were short phrases that served as proprietary URLs within the AOL portal; for instance, you could navigate to the cryptic "http://www.oprah.com" or you could simply type "OPRAH" into your AOL keyword bar and be taken directly Oprah's special page hosted on the AOL network. Guess which one most people used?
Given the popularity of America Online as an ISP, its web portal tended to be the center of the layman's web browsing experience. Everything you could ever need was found with AOL's carefully administered walled garden, so the casual web user really had no experience with the World Wide Web at large. For big businesses, this fact meant that it was crucial to establish an AOL keyword so they could be found by the quarantined masses of AOL customers.
The public's eventual awareness of the rest of the free and open Internet was precipitated by the ".com" boom, better search engines and the demise of AOL. But it seems we are taking a step back to the Dark Ages of the 90s. Facebook fan pages have usurped AOL Keywords as the modern alternative to the publicly accessible Internet. You rarely see organizations publicizing their webpages anymore. These days, they just say "Become a fan of [whatever] on Facebook".
The parallels are frightening. Like the AOL network, Facebook is entirely proprietary. All content hosted on Facebook is only accessible by people who have signed up to be members of the site, just like AOL's web portal was only available to its subscribers. Today it is still possible to find copies of regular webpages that have been up since 1995. But there is little to no record of the pages that were hosted on the AOL network from that time. The same will happen to pages on the Facebook network if the social media giant were to crash.
I don't wear a tinfoil hat and try to live off the social media grid. I have plenty of my own data locked up in Facebook's proprietary social graph. But I will readily admit that these closely guarded walled gardens are subverting the Internet ecosystem, depriving it of content that is meant to be freely accessible through open standards. Perhaps we should consider that for posterity.