I had a real slump in posting on lj not long ago that was when I discovered Tumblr. I love it but I am back to LJ now too that rl has calmed down, I find that you get the most out of LJ if you read and comment on your flist as well as posting yourself, and sometimes I don't have time for that.

Tumblr is excellent, all my rl friends have one and its a great way of sharing and remembering/storing cool things you find on the internet.

Not a fan of Twitter though and I would never fully leave LJ, tumblr is a completely different experience.