Slightly dodgy tip on how to get some extra traffic
 

If your host hands out IPs without needing justification, ask for more. Then monitor them to see if there's anything still pointing to them.

It's like grabbing an expired domain, except this time you're playing expired IP lotto...

This trick probably only works with big hosts that have a large number of clients dropping off at any time (eg theplanet) and remember the previous usage is likely to be mainstream related

:thumbsup

There could be still traffic coming from those IPs, yeah.

this could be a tip for hosting companies also

lolz

sounds unlikely that you will get any worthwhile traffic from this strategy...

Is there an easy way to find out what domains were associated with those IP addresses?
WG

It's hit and miss. It's worked for me, but perhaps I was just lucky.

WG, you can set up apache to log the hostname that the browser thinks it's connecting to. Some sites also offer reverse IP->domain lookups.

How much traffic or $$ per day did you get using this trick?

You could score a bad IP this way as well. If you can find a way to trace the old domain it's not so bad.