LiveJournal only shows entries your friends have made in the past two week. However, this does not appear to be documented in the FAQs anywhere (one user I asked about it even told me he had gone through every FAQ looking for "two" or "week").
DeadJournal documents this; it would be nice if LiveJournal did so, too. (Perhaps under "limits on data", FAQ 148? Or a new FAQ about Friends Pages in general? Or under Troubleshooting?)
The number of entries in your LASTN view (75 on LiveJournal, I believe) before it goes over to Calendar should also be documented somewhere; I don't think this is in a FAQ, either (though I'll admit I haven't looked that hard).