Got no idea. One of my domains got a sudden bump on the traffic since 3 days ago (from 200+- U/D to 2000 U/D!!). It didn't surprise me, however, since it was close to that level at Sedo before. Reasonably, the CTR remained the same - 6~7%. I tried to boost the CTR, but each time I changed keyword, the CTR kept on dropping. Now the traffic is slowly going away.
Could it be ads being displayed differently in different regions?
I believe the main audiences of that domain is located in Europe and South America. Many are Hispanic. Irrelevant ads may have been displayed in the targetted regions.
hummm...