It's been happening for several months in some sectors and especially so the construction industry.
Comparing January 2008 to 2007 metrics my Leaderboard EPC is +15.31% however my AdLinks EPC is -19.73% and whereas my Leaderboard used to have 52% of the clicks it is precisely 50/50 so far in 2008.
Couple that with a lower CTR, therefore consequently a lower eCPM, then earnings are seen to drop significantly.
Dare I remove the AdLinks?
Maybe people like EFV have not seen these dramatic falls since his fellow Elbonians are much wealthier with solid disposable incomes?
Are his "relations" in other travel sectors from Lower Widgetville possibly the more budget-conscious sector of sites?