In the posting Getting to Know You, Tristan Lewis speculates on Google's motives for providing their new Firefox extension, Blogger Web Comments. The analysis makes a lot of sense, and is probably close to the mark. I'm glad someone is reading the License Agreements for me.
I had already installed the extension before reading the post, and probably would have taken the risk of keeping it installed for a while. However, I've recently been having runaway memory problems with Firefox on my Debian GNU/Linux system. At first, I had attributed it to upgrading to the latest "firefox" package in the Debian Unstable repository. Then, it struck me that it was quite possible that Google's extension was to blame. The timeframe seemed right — the swapfile thrashing and glacial response in Firefox has only been happening for the last few days.
So, I've uninstalled the extension.
So far (a couple of hours), no more runaway memory problems. I tend to believe that the Google extension was the culprit. If the memory problems come back, I'll update the post and try to lay the blame elsewhere.
UPDATE: The Google extension has been exonerated. Firefox caused another memory-eating episode today, with the extension removed. In the meantime, Debian Unstable has moved their "firefox" package from the repeating-decimal version 1.4999... to version 1.5. I've updated, and now I wait to see if anything has been fixed. You know what would be nice? If Debian's package-management system would show some sort of changelog.