Attention! This requires lots of reading.
~
Sorry, I didn't intend to write a documentary, I just find this an interesting thing to discuss.
I've been wishing to make my dinosaur RP, but I've just been lacking motivation to write everything down that I must to even post the thing out for others to sign up for, and I fear that if mine does become good, then someone else is just gonna copy it and say "it's their own unique RP" and then that one will take off even more than mine did.
So I do understand what Salt Shaker means, and I do feel the same way sometimes. The only RPs I really ever sign up for anymore is Imperial Sand's RPs, because they do an awesome job keeping it unique.
I think most RPs either greatly lack literacy, or expect you to write a whole page-long post. And maybe most of the reason why lots of RPs die, is because everyone gets bored of writing an infinite series of one-liners or 2,000+ words every three days to keep up with RPs. I think the reason why Fangoffire's awesome Strive to Survive is really keeping up and alive, is because no one has to make 2,000+ word posts, but no one can make less than 150 words. It keeps others wanting to keep RPing it, because they don't need to spend 2 hours of their day, writing a post for an online wolf game when they could spend much more time doing other stuff.
Also another reason is because lots of players will just disappear the moment there isn't at least one post a day. I don't know if this is entirely true or not, but in my past RPs, this is definitely how it felt. Don't leave a RP the moment someone doesn't make a post at least once a day. Seriously. Remember that others have their own life outside of WP. Not like me saying this would help at all, since in every RP it at least says that once in the rules, and no one listens.
Now back to the literacy, I do think that literate RPs could live for a long time, and keep going for a long time, if they weren't as demanding. Like Spellbound seems to do a great job at ensuring that no one only posts once a month, but also giving others some time to do their posts, without having to spend hours just writing one post so they don't get kicked out.
Another thing is, I think the RP hosts don't enforce their posting rules enough. I've vanished from some RPs for weeks, and never once got PMs from the RP host, and when I return, they don't even question where I'd went for so long. Now I'm not saying to send someone a PM the moment they've taken a day over the limit to post, but just don't completely ignore the fact that they disappeared, since others will probably be waiting on their posts.
I agree with Moose on the talk about writing quality. I think writing quality does greatly impact the success of a RP. If someone writes too little, everyone is just gonna try and find a different RP with more literacy, and if there is too much, no one is gonna want to read all of it.
This may be edited later.