I installed an Akismet update a few days ago when it came out, and a few days later my site stopped working -- when comments were posted they were empty, when I tried to add a new post I got "submit for review" rather than "publish" as the blue button to the right. The new post never appeared anywhere in the database.
After reviewing other things I did recently, and trying to find the problem, I noticed that the size of the database was 150M. 1and1 hosting plans all have a 100M "limit" on databases.
I removed another plugin that had never worked successfully for me and was using about 40M of the database space, then looked at the commentmeta table, which was using 50M of the space. Turns out it was almost entirely Akismet data on spam comments. I had 3600+ spam comments -- I've not been consistent in removing spam comments identified by Akismet, and it's never caused a problem in the past. (I would love to have the program auto-delete comments that are more than a week or two old, as frequently a day or three later someone will email me asking why their comment didn't appear, and I'll find it in the spam folder.)
I do not know if it's the recent Akismet update, or if it's just been slowly growing and finally caused problems, but ... I deleted all spam and it reduced the size of the commentmeta table from 50M to about 60K. My site now works perfectly again.
I'm posting this in case others have the same problem, as well as asking if anyone else noticed this. Is it the recent Akismet update, or do I just need to make sure my spam count is kept low.