Also, some comments from Danny S. in this Wall Steet Journal article [asia.news.yahoo.com]. Registration to read is NOT required to read full-text.
The momentum that AdWords has is pretty amazing. English + 10 non-English languages, geographic targeting, options for content ads--it's exciting to watch.
naturally with the low entry expense, many a webmaster has gone and opened an account, and then never used it to its real potential.
Overture on the other hand has a slightly higher entry cost, combined with a few more headaches getting campaigns live.
Although I have NO data (sorry GG, your girls in the UK wont share that sort of sensitive information with me, even when I told them it was to help you), I reckon quite a number will be -$1,000 per year.
Shak