I’m on a couple of pinglists and it’s not uncommon these days to get multiple pings. Interestingly enough, I seldom do from PJ-Comix’s DUmmie FUnnies. Maybe it has something to do with coupons? ;-)
Several years ago when I did a big list, I used to get a “Session Timed Out” window, requiring me to go back to the Forum from scratch instead of being returned to the thread automatically. It usually made me wonder if the entire list pinged. However, the entire list did ping — I found this out by FReepmailing the last few names on the list from time to time and asking if they got their ping. (They did.)
The secret is to CLOSE the window about two to three seconds after hitting the “POST” button. That seems to work.