Yahoo, contextual ads and switching costs

Umair at bubblegenrations comments on the Yahoo Mail and resources comment I made a couple of days ago. Sometimes I wonder if he isn't a bit too into strategy (in a good way, though) for me to truly understand his reasoning, but still I have some comments.

I don't agree with the notion that Google has a significantly more trustworthy consumer brand than Yahoo, especially not among American users. I'm not sure that contextual ads in an e-mail environment is good for the advertiser, nor am I sure that e-mail providers will be able to sell the idea of such ads to their users (the privacy concerns). If Google can sell their users on the idea of contextual ads in Gmail, I don't believe that Yahoo won't be able to do the same to users of Yahoo Mail. Basically I think users believe both corporations will treat their private e-mails confidentially and chose the service that they like the best. So switching costs won't be affected in a major way by contextual ads alone. But, that's just my 2 cents...