[quote=Queen Raidne]
Certainly a lack of posting can be claimed to kill all RP's. But why don't people post?[/quote]

Contra had a nice list on this pre-guildfall. There's a variety of reasons, but generally the issue is a lack of investment and susceptibility to "Well if they don't post, I can't post." Which I like to call chain-quitting.

[quote] What can you do in creating and running a roleplay to avoid these things?[/quote]

Get people more invested in your RP. Make their actions feel significant, move your events quickly instead of lounging 4 pages at the local tavern doing nothing of note (taverns kill RP's) godmode the fuck out of drop-outs, have a good amount of luck, but most importantly; communication. OOC's are fantastic for that, but skype- or steam-groups work as well. It doesn't have to be about the RP, even, you could ship Winnie the Pooh characters with George of the Jungle for all I care. As long as it brings people together, it'll help you a lot. They become more invested in the social dynamic of your RP, which is a great reason for them to keep coming back. 

The beginnings of games are far more fragile than ones that ran a couple months, but in the beginning you should always have a plan for drop-outs. They're going to happen. You're going to lose people in every stage of your RP booting up, including the first months of the IC. This is why doing things like making a plot reliant on certain characters is a no-go, unless you as a GM feel like juggling it all (at which point people often feel you're focusing the RP more about your characters than theirs and the whole thing falls apart.) Something I found to work quite well, was to find ways to brutally murder dropped PC's, because it gets people to think and talk of how they'll be killed, we can have the scene affect the active characters by having it play out in front of them, or even use it to mix up the plot.

There's a lot more things to do, but little time to write it down so yeah this may or may not be continued.