As seen on status
We're currently working on addressing issues that are causing LiveJournal to be slow to load (or fail to load entirely).
Additionally, we've been dealing with an increased amount of malicious traffic recently. In order to ensure LiveJournal's overall availability, we've take a couple of measures to minimize the impact of this traffic. Unfortunately, this has the side effect of preventing some users from posting long entries or comments. We're working on resolving this problem as soon as we can, and we apologize for the frustration it's causing.