I think the Social Media website market is getting way too crowded. You cant expect everyone to keep up with more than two or three of these websites. I know the younger generations hop onto to these pretty quickly but its usually at the expense of users from other Social Media sites. You cant expect a website that does exactly what other sites with already established user-bases to get much traction.
In today's culture, everything is so fast-paced and constantly changing, I think the life span of most new social media apps will be short. Facebook and Twitter are anomalies since they were leaders in the social media scene. But newcomers like Vine will have a difficult time gaining ground. Vine had too many competitors like YouTube and videos on Instagram. I think Vine was fighting an uphill battle from the beginning.
What did Vine contribute to the internet or social media that other apps and programs did not? That may be a legitimate question in that I have no idea what Vine is or did, but it seems highly likely that in a saturated social media environment, more than a few will fail before the fall of Western civilization.
Vine was supposed to be an everyday video sharing tool, but that didn't really happen. It's users wound up experimenting and doing some out of the ordinary things. Maybe it failed because its competitors developed the ability to do similar video sharing without the time constraints. But I don't think it was necessarily doomed to fail from the start.