"A proxy bid should operate the same as a snipe, in theory, but I'm wondering about that 10 seconds or five seconds thing. If I'm high bidder with a Proxy and someone outbids me, but hasn't reaced my Max. yet, does the auction just close?"

If they outbid your bid that's showing, but they don't outbid your max, your bid would be pushed to the next increment over their max.

You have a max $15 bid, but only $4.99 is showing. The next bid is a snipe five seconds before the auction ends...the bid is $10...it will push your winning bid to $10.50 and the auction will end.

OR...another bid comes in, for $12, one second before the end.....your $10.50 is pushed to $12.50, and the auction ends.

"Also how does the sniper software manage to bid high enough, without making an excessive bid, which some other sniping software will detect and create a critical mass?"

I don't know anything about sniping software...but I'd guess that the software simply places a proxy bid for you, at the programmed time. Our $1000 bid didn't show as a $1000 bid, it showed as $702 (or whatever it took to win the auction). I assume that sniping software would have placed a $1000 bid, just like my husband did?

"5 seconds isn't enough time to allow for a counter bid?
There's something wrong if there are two or more snipers working at the same time, and I'm sure that has happened. The higest sniper won't win, but the last bidder will."

Again, I don't think the programs are bidding against each other....they're placing the max bid that was programmed into them, at the time that was programmed into them. It IS the highest bid that wins.

Say an auction is at $100, with 3 seconds left.

If you've told your snipe program $500, with 2 seconds left in the auction....

If I've told my snipe program $300, with 1 second left....

YOU will win the auction, with the high bid. The high bid will be $300 + whatever the bid increment is ($5? $10? whatever?)