I agree with all your points re: taking the friction out of the equation. However, I think it's more to do with the fact that you share with individuals rather

I agree with all your points re: taking the friction out of the equation. However, I think it's more to do with the fact that you share with individuals rather than to a feed that makes the difference. Not so much the fact that it will sort of vanish after it gets viewed (less so now that they can get replayed) When you share to a feed you'e sending it out for everyone to see. You want to know that people saw it and with services like Instagram and Facebook this is done via commenting and Liking/Favoriting. With Snapchat you fire and forget. No one needs to like the picture in order for you to feel any sort of satisfaction. The only indicator you get is that it was viewed at all - and with the sort of content that gets sent over Snapchat, that's really all the information you need anyways. TL;DR: I think the "choose indiciduals to send to" model is more important than the "they get erased" aspect. Of course, the vanishing part of it is what got Snapchat to become popular in the first place so it would be wrong to say they would have seen the same amount of success without that feature. However, at this point, I don't think that is what makes users keep using the service.