Come to think of it [H] is on vB and sometimes runs into issues as well. It's actually kinda odd because vB is a really expensive product so you'd think it would be much better at handling large databases.
I'd have to get my hands on a copy to play with it but my guess is that it does not self cleanup after itself such as the entries in the session table, and it just grows out of whack. The "maintenance" is probably the purging of old entries in this table. Though, it makes no sense a simple DELETE WHERE command would take 5 hours on modern server hardware.
Definitly hilarious to see all these issues considering it's a tech site though. It's almost as hilarious as Symantec getting hit with a huge virus.