Exchange 2007 makes use of transport rules in order to tag emails with a company disclaimer. But, the 2007 transport rules only allow us to add plain text as a disclaimer. It does not allow us to pull the user info from AD (like Office, Company, Phone Number) and add it in the disclaimer.
Exchange 2010 has rectified those two drawbacks! You can add Html content, links and pictures to your disclaimer. Similarly, you can configure transport rules to pull the AD information of a user and populate those in the disclaimer, just like the present third party applications does.
2007 & 2010 disclaimer part of the transport rule looks alike and the steps for creating a transport rule remains the same in both versions. But 2010 gives you the flexibility to add html codes.
The AD attributes of a user has to be written within double percentage sign to be shown properly in the disclaimer (eg, %%Display Name%% will pull the user’s display name from AD). Finally, we can depend on exchange for our company disclaimers ;)