And there's already a new temporary community: ohnotheydidnt.
The new ONTD is already at 21,000-plus comments. How long until 2^24?
Let's look at some other comment stats for large communities. Here are the top five that I could find:
ohnotheydidnt: Created on 2004-06-26 23:26:18 (#3616053), 16,199,244 comments received
thequestionclub: Created on 2002-07-19 16:36:12 (#636604), 5,735,099 comments received
customers_suck: Created on 2001-11-05 20:47:56 (#386231), 1,671,431 comments received
ask_me_anything: Created on 2002-02-18 11:11:38 (#471900), 1,393,058 comments received
sf_drama: Created on 2007-08-31 20:16:32 (#13720169), 936,090 comments received
Hm. sf_drama is the newest of these five (followed by ohnotheydidnt. They'll run into this limit...oh, in a year and a half, two years. The others have a little longer, but maybe by then this bug will be fixed for good, and ohnotheydidnt can break LJ again.
In dog years.