Moncao - 4:11 am on Apr 17, 2008 (gmt 0)

Click bots
If it is the same as when Yahoo employed click popularity ranking in its se algos, it works like this;

One PC, many simultaneous connections
Use AOL and get dynamically assigned IP’s on top of proxies and IP faking
Use rotating browser types (including your OS version)
New user, get Yahoo cookie
Click one - Search Yahoo regular index for unrelated item, cookie changes.
Click two – Search Yahoo for another unrelated item, cookie changes again.
Click three – Target click.
End (cookie gone – you appear to have stayed on the target site for ever).
If you are working off broadband, you are talking 20 connections per PC, 20 efficient fake users doing you bidding per PC. I suspect they now require a user to come back again to validate their pay per click use; easy enough to do.

In click pop days you would short click your opponents sites to make it look like their sites did not have relevant content (appear to stay on for 20 seconds or less – the number of seconds randomized), as Yahoo down-ranked for such short stays. Clicking for pay for links is actually simpler.