I found a great article about optimizing your site for MSN and Yahoo that I wanted to share. Here are highlights:
For Yahoo:
Likes older sites with quality inbound links
Likes sites that are W3C Compliant – so make sure that it gets the OK through Bobby (online compliance tool) and that you’ve filled out your alt tags!
For MSN/Live:
Website age is not as important
Likes large sites with lots of good, unique, relevant content
Doesn’t require as many quality inbound links
Happy optimizing!