Platform, lol. The site was better before the platform enabled apps. The entire platform is faddish, it's popular because it's popular and everyone else is doing it; until they aren't, then you stop. There are billion dollar industries that are entirely based on fads, movies, music, games, or fashion for example. The amount of money has no bearing on whether something is faddish. For most, facebook is entertainment, the entertainment industry in all its forms is all about fads and popularity.
Every company is around until it isn't. Blockbuster just declared bankruptcy -- does that make Blockbuster a fad?
Facebook is six years old. 500MM people use it every month. They are profitable and do over $1Bn in revenue. They have a platform, on top of which there is at least one $1Bn company (Zynga).
Groupon, also a $1Bn company, owes its success in large part to Facebook's ad platform.
Facebook is now moving into location and online payments. They will compete with PayPal, another $1Bn company (before being acquired by eBay).
Zynga is PayPal's second largest merchant, after eBay itself. Through Facebook credits, Facebook will be taking 30% of each of those transactions. They are building a database of credit card numbers to do it.
Tencent QQ, a Chinese social network with gaming elements -- most of the popular genres on Facebook were taken from popular Chinese social games, e.g., the farming genre -- is 15 years old and did over $1Bn in revenue last year.
Tencent's IM product has 610MM monthly active users and 63.2MM people with subscription accounts.
Sure, fine, there's some universe in which Facebook vanishes tomorrow. The demand is still there. Social networking is here to stay.
The only way Facebook will fall behind is if they slow down and let someone else pass them, but given their history of aggressive and forward-thinking innovation, that seems unlikely for at least the next 5 years and/or until Zuckerberg stops caring.
And "it's popular because everyone else is doing it" -- you just described every business built on top of network effects. Craigslist is popular because everyone is using it. Does that make Craigslist a fad? eBay? VRBO? Etsy? YouTube? HN?
Pet rocks were a fad. Slap bracelets were a fad. Snuggies are a fad. http://fmylife.com is a fad.
Do you really think Facebook is that? Really?
I also notice that you didn't cite a single piece of data. Do you have any to support your argument, or is it just your "intuition?"
I didn't say Facebook was going away, or that it wasn't big business, nor did I say Facebook is a fad. I said he rode a fad to fame, that means it was a fad and then it became something tons of people use as it fleshed itself out over the years. If you don't agree, then don't, I don't care; don't get all bent out of shape about it like I insulted your mother or something. I don't need to quote sources to state my opinion.
Facebook's as much as a fad as photo-sharing, sending people messages and joining a discussion forum. Zuck originally said he wanted the relationships on it to reflect real life. The only thing faddish about it, is people's willingness to share their lives on it, and that's what Zuck wants to change, he wants sharing and exposing oneself to be normal, after all, for him it's all lulz. It's the over-exposing that is a fad as people start to want privacy.
When it first came out, I thought this is just like a friggin Xoops installation customized for college students (but custom built, and carefully sold to the right people). Also, a lot of Web 2.0 ideas were just like Xoops CMS modules (or WP plugins) but scaled out and adapted for mass website usage. The Facebook platform is just like Xoops module deployment that users can customize for themselves rather than the webmaster.
Theoretically, the only thing that could take out Facebook or come close, would be some type of cross-language, cross-server middleware layer, that webmasters could use that would simplify and improve web development, and give broad social, ecommerce, presence and whatever other features are, or will start to be in common. FB is in the best position to do that, and that's what I expect to see going forward: it'll have to create standards and protocols (an open source FB server?) and release those into the community.