I am perfectly fine with short posts as to length (Write them all the time... haha)
However I feel it is needless to add "-s-" at the end. I mean if it's a roleplay where just about everything is a really long post I kind of get it if you say "Sorry, short" or as an explanation that you just are not up to long posts today.
When someone writes a shorter post, although nothing is wrong with the post it just isn't over the top. kind of.. "say it like it is" kind of post I really feel there is no need to add "-s-" because everyone reading it can read it and tell how short or long it is. not that adding "-s-" is a bad thing, But it gets on my nerves. I'll still play with people who do it, but I'm not really sure why they feel so compelled to write that out for me.
As long as you can clearly understand the other users post, I'd say that's alright, as long as their post has enough so you can continue the roleplay, it's all right. some people also have a comfort zone, start small, go big.
But really, if your post is short, I can tell, you really don't have to spell it out for me.