The rather egotistically named GreatestJournal which for a while seemed to be the primary and preferred refuge for those displeased with LiveJournal's actions has been in trouble for some time. During or not long after the
StrikeThrough mess so many new accounts were made and being used that the load showed, badly. GJ tried to not have any fees or ads at all and evidently whoever ran it was not independently wealthy and able to buy upgraded service and gear. The originally rather generous amount of user icon space dwindled in an apparent attempt to free up space and cycles. The system wound up getting slower anyway.
I'm not sure when, but several months ago it was announced that no new accounts could be created and no new development would take place on GJ. Old accounts could be still be used, but backing them up was a Good Idea. The create an account page had a message recommending InsaneJournal. This lasted some considerable time.
Today the GreatestJournal main page is a 403 Forbidden message and a suggestion to go to LiveJournal (which has bewildered a few folks on InsaneJournal). There is also a note that those who still have accounts can use ljarchive to (finally) make a backup of their GJ account. This note points to the LiveJournal ljarchive community. Since there is a note that user can do that backup, this does look like a progressive shutdown rather than temporary issue.
I suspect that if this has any relation to the current LJ news at all, it is minor. It might have been that an influx of users with dormant accounts attempting to use them for LJ backup caught someone's attention and rather than deal with the bandwidth and such, it was just time to put an end to things. Or it is complete coincidence. As for the fallout from GJ going away, I don't expect all that much. Most have likely stuck with LiveJournal and only had dormant GJ account as insurance. Those that truly fled LiveJournal are likely to have already moved or at least have a backup account on InsaneJournal or DeadJournal or the like. I don't know how many still actively used GreatestJournal. That seemed foolhardy to me for some time, which is why I gave up and deleted my GJ account many months ago. It was quite clear that GJ would not last. The real surprise is that it has lasted as long as it has.