For my money this will be a shortlived phenomenon. There is already the issue of googlegangers (people who share your name and consequently turn up when other people google you.) It is only a matter of time before somebody gets badly burned because of somebody else putting up a fake defamatory profile of them (whether malicious or funny-ha-ha). Cue wringing of hands, media inquisition, overwrought Daily Mail editorials, over-reaching legislative remedy, eventual return to sanity as per the usual Internet Wash Cycle:

1) Discover that X is available online

2) Discover that X available online may be slightly less than totally reliable

3) Rinse and repeat

After that, of course, it's only a matter of time before "I didn't write that, it's somebody out to get me" becomes the standard defence for having your embarrassing online juvenilia unearthed.