''I'm a PC'' on MSN
If you go to MSN now, you'll be hit over the head with the I'm a PC ads. I think it's a bit over the top, giving you a movie playing automatically and a ton of images around the border. You can turn these images off pretty easily, but it's a bit too in your face for me. What you may also notice is that the ads and the border are done with Flash. Why not Silverlight?
I have to say that I agree with this decision. For something like advertising, you want your message to get out to as many people as possible, and right now, the best way to do that is Flash. The ugly truth is that there just aren't as many computers with Silverlight installed, and that's not a secret.
However, if you click on one of the ads, you'll end up here: http://imapc.lifewithoutwalls.com/
This site is done mainly with Silverlight, and I think it's pretty nicely done. So Flash for maximum exposure, but once someone is interested in learning more, they will probably not have a problem installing Silverlight for that. I think it makes good business sense and is a good balance of using their own technology versus getting the most eyeballs on your message.