Can you tell who has read or seen your posts? I guess I mean, when I talk to someone I know they are there. I don't want to feel pressured to look at the feed every day on the chance of missing something.

I feel like the people I talk to, I already talk to. Internet people are internet people - and I'd like them to approach my missives at their own pace. Not have an inspector-gadget like timer associated with the posts.

You can tell which one of your friends has viewed your posts on your personal timeline or directly

Except that you are not - if I talk with somebody for real, at least I know somebody listened to what I say (OK, or at least pretended to listen). Seems as if I could go through the effort to snap something and it would disappear before anybody sees it.

Does it also play on that basic human condition of not wanting to see options go away, so you frantically click through your friend's stories for fear of missing anything? I could imagine how that would get users hooked, but I wouldn't consider it a good thing.

But why should interaction disappear if it doesn't have to? Snapchat is no more like talking with someone than Facebook Messenger is, with the exception that you get to keep your interaction with Facebook Messenger.

While I "get" your point, I think it's a stretch in terms of what Snapchat offers that I can't get elsewhere with a better experience.

But then, I'm well over 20 and from the comments on this post, definitely not snapchat's market.

The reason snaps disappear is to enable one of the key effects of Snapchat which is low-stakes social interaction. Users feel they can be more relaxed in their interactions when they cannot be recalled later. To quote the article:

    There’s no public view count, follower count, likes count, or any other social
    dick-measuring contest. You can just put whatever you’re doing on Snapchat; if
    people don’t like it, who gives a fuck, you’ll never know. There’s no
    expectation of balling out 24/7.
    
    Consequently, on Snapchat I’ll post to my daily Story almost twice as much as
    I’ll post to Twitter and Facebook combined to reach only a fraction of the
    number of people. The cost of content creation is extremely low, and Snapchat
    makes it fun to think about what aspects of what I’m doing every day might be
    cool for other people to see.

Many people do feel social pressure to be "cool", to perform to the perceived expectations of the groups they belong too. Given that, many people clamor for "lower stakes" interactions. While the same "lowering of the stakes" could happen at a social level, and I believe that is something that's happening slowly over the long term, a much faster route is to use a tool that enforces lower stakes, such as Snapchat.

If you are someone who does not find the appeal in low-stakes interactions, then it's quite understandable that Snapchat may not appeal to you.

No, Facebook Messenger is like talking to someone with a tape recorder sitting between you.

Compare it to Twitter limiting your communication to 140 characters. Or Instagram limiting your posts to photos (as far as I know; never used it). Or Vine limiting you even more than Instagram. Or Tinder limiting you to swipes (compared to pretty much every other 'dating' app out there).

In all cases the limitation is rather arbitrary, and yet one of the primary defining aspects of each product. I don't think it's a stretch at all that the ephemeral nature of Snapchat is its main offering. I kind of wish more of my friends would use Snapchat, because I'm not always happy with the idea that everything I ever said to a friend via Facebook is stored and can be read and searched by them. And by Facebook.