I am weird. So I just logged into my Yahoo! Mail and Hotmail, which I haven't used for years. I sometimes log into them to see whether Yahoo! or Microsoft has any hope.
Nope. They have no hope. They put too many links and social stuff in email interface. For example, Yahoo! always prompts news (the "What's new" tab) on the first page of my email. I am not there to read news but checking emails.
So, I come up a theory of user interface design: one function to users per time.
PS: One thing really bothers me is that we don't have good alternatives to Gmail. There is no Internet company that I can see to compete with Google on many products, such as email.