I don't think this is a good idea. It's doubtful that it increases efficiency much, since you still have to cut and paste a link. Also I believe it would encourage people to post more code, and we don't want code to be too long. If a piece of code is that log to begin with it's probably doing too much anyway. Longish is fine, and I am against placing an arbitrary limit on a post. However, if you post too much code people won't really want to wade through it and both the questioner and the site loses.
EDIT: As previously discussed, not everyone can get to pastebins depending on firewalls, etc. Embedding code will still suffer from this issue.