It seems like not a week goes by that another story flies around Facebook about impending "charges". There is one doing the rounds now!
I think that like many other innovations on the web, someone somewhere is developing the next "big" thing. Do you remember Friends re-united. MySpace? These programs had their day in the sun and then seemed to vapourise. Facebook has been a tremendous tool for keeping people in touch; but the technologies that it uses are not new and had in fact been around for years under different names.
There are better programs out there and it is just a question if anyone can be bothered to move to them. If Facebook does attempt to charge for their service then that may be the motivation people need to move to other platforms.
Is it doomed? Do you remember Alta Vista, Mosaic? exactly.
And really does Facebook need to make any more money?