Hi, readers!
With the help of Persistent Reader Liz, I've found a defect in the anti-spam setup on the stblogs.org server, a mistake that was keeping legitimate users from commenting. (I am so sorry for the mistake and the inconvenience!)
If you had trouble commenting before, give it a try again, and see if things are working better for you now. I'm not sure that this fix has cured all the aspects of the problem.
Yay! Thank you.