Office - Automatically change incoming message colors and fonts based on sender, subject, or recipients

Conditional formatting is a way to make messages that meet defined conditions stand out in the message list by using color, fonts, and styles. You specify conditions that an incoming message should meet, such as a sender’s name or email address, and then conditional formatting is applied only to those messages.

For example, a conditional rule can specify that all messages sent from your manager appear in red text in the message list.

Here is the relative article:

http://office.microsoft.com/en-us/outlook-help/automatically-change-incoming-message-colors-and-fonts-based-on-sender-subject-or-recipients-HA102054868.aspx