OK, here's a little more background for those who want to know: After my post on Feb 7, the next time I tried to post, my Blogger screens displayed no buttons for allowing me to complete my posting, and in addition I got error messages. This happened identically in Netscape (my usual brower), Safari, and Firefox. I installed the latest versions of each of them just to be sure.
I had installed no new software since the last week in January, so it didn't seem likely that any of that would have had an effect.
Indeed, it didn't--software I installed at the beginning of December, many many blogger posts ago, NetBlockade, disables something that Blogger now appears to be using, because when I disable NetBlockade, Blogger now works correctly.
So I'll try to catch up on My Life With Agility Dogs over the next few days.