Yahoo continues to inject social networking into its services.

Starting later on Monday, Yahoo Mail users will be able to update their Facebook status from their Yahoo Mail in-box. Facebook users will be able to log into their accounts right from the Yahoo Mail home page and will also be able to click through to the Facebook profiles of friends when they receive e-mail from friends who have linked their two accounts.

It's a small but interesting update to Yahoo Mail, which is the most widely used Web e-mail service in the world, according to ComScore statistics from last year. Yahoo has tried to get its users to think of it as a social-networking service unto itself, but there's no real competing with Facebook for that kind of attention.

Still, Yahoo has made social media a priority for 2010, and promised Monday to unveil new features throughout the year.