When does a website, like a social network become highly profitable?

[mrjorgito]

In the case of "facebook", if initially it didn't offer any publicity, how could facebook survive? Where did the money come from, during the early days?

If you have a big traffic volume alone, and no ads displayed, how can you make money? How can this situation attract investors?

Likewise, how could "youtube" survive during the first months of rapid expansion?

Could someone please enligthen me please ?

[barenakedchicken]

Same way Linux or any open-source programs are surviving, they dont offer ads, they dont buy ads from other companies, so it would most likely be from word of mouth,,,,that sounds like the most plausible idea...