For fun, I've been following a GB auction on a Python that has a lot of bids. It's a ten day auction that ends on 3/3... Started at a penny with no reserve.

I have a question about the auction tactics that I see here. The same bidders continue to raise their own bids, which seems to make little sense to me...especially at this point in the auction.

Here are some of the last bids (with the bidder names disguised) to illustrate what I'm talking about. The current bid is $3100.

Can somebody help me understand the strategy?