Didn't people say the same about instagram and twitter? There are services that have the ability to stick around.
Twitter is an indispensable communications medium that has more than 1 use case (read news, talk to friends, overthrow a government, etc). Thus ads makes sense (and I would even pay a low, yearly fee to keep it around).
Snapchat is interesting, but $100 million interesting?
However, note that everything you read is not necessarily true. Unless you have HARD DATA, whatever you read may very well be made up.
"Didn't people say"