As I've said here before, we got hit by Panda. When it happened, we boned up on all relevant Panda information - everything coming out of Googlers, conferences and other SEOs, and decided to make some big changes, one of which was rolling back our Adsense (not completely, but we have massively cut back). That was 2 months ago, and to be honest, it's had very little effect on our user metrics, and it certainly hasn't got us our traffic back to pre-Panda levels.
So here's what's happened:
(1) Panda reduced our traffic by about 40%
(2) That obviously reduced our revenue
(3) We then decreased our level of advertising, voluntarily reducing our advertising further
(4) We've seen no traffic increase
This has been going on for 2 months now, and puts us in a difficult situation. If we're not going to see a return to pre-Panda traffic, then we may as well just roll back to our previous Adsense configuration - after all, it didn't really appear to effect user metrics (BR, TOS etc...) However, if it's just a case of waiting for Panda 2.3, then we may as well sit it out.
How long would you sit it out for?