[qjz]

I think you skipped the most important statement in the article:

"Check the value of Bebo, Myspace, Friendster, etc. and you'll see the future of Facebook."

What makes Facebook any less fragile? Perhaps social networking sites are intrinsically subject to the whims of fashion.

[gilbertl]

Replace "Bebo, Myspace, Friendster" with "Altavista, Lycos, Infoseek" and we've an argument that Google has no future as a search engine.

Facebook has been less fragile because it has provided more value for its users. That they have a 500m users locking in each other is a bonus. Whether Facebook continues to thrive depends on whether they can fend off competitors.