The LJ syndicated feed of Brad DeLong's Daily Journal quit updating a couple of weeks ago, so yesterday I checked the syndication status on the feed's user info page. It said that the last time the site was checked, it was "too big" to fetch. Today, it says the same thing. The last update of the feed was March 6, so I checked DeLong's archive and found that, within a period of less than an hour (the frequency of LJ's checks for updates on sites with feeds), he had posted three entries, two of which had graphs in the form of .jpg files totalling almost the whole 300KB LJ allows for a feed. The text apparently put it over the top.
It seems that when LJ checks for an update at any given site, if there has been no update recently fetched it looks back through quite a few unfetched entries, and as a result of this action the amount of material that would have to be fetched to update the DeLong feed has been greater than 300KB ever since those big entries of March 6. This happened to the same feed about a year ago, and it was several months before it began updating again. This makes me wonder how many LJ syndication feeds get cut off in this way, and for how long? I'd say there's a design flaw here that makes LJ an unreliable source of syndicated posts, and despite the convenience of having the feeds on my friends page I'll probably switch to another source altogether.
I'd expect that there would be a some way of fixing this glitch in LJ's syndication system, but the fact that it's already been there for over a year suggests to me that it isn't going to get fixed anytime soon. I also doubt that putting in a support request would do any good. Checking the request board, I saw a couple of old open requests concerning other feeds classified as "too big", so it looks as though the support volunteers are clueless on this issue. Heh. LiveJournal, where everybody gets to twist in the wind together.