VMware appears to have been setting the stage for the elimination of VMware Server, which was also known at one time as GSX Server.)  As noted over at Planet VM:

Here are a few signs. Like the one that VMTN user Borja Mari noticed the following text in a security advisory VMSA-2010-0007

“End of General Support for VMware Server 2.0 is 2011-06-30, users should plan to upgrade to the newest release of either ESXi or VMware Player”

Another uncomfortable sign is that there haven’t been any updates in almost 7 months as you can see on the download page where the last version is from 2009/10/26

As someone also notes:

You should also check the note below the VMware Server table in the VMware Life Cycle Policies document: http://www.vmware.com/support/policies/lifecycle/general/#policy_server

VMware Server was declared End Of Availability on January 2010. Support will be limited to Technical Guidance for the duration of the support term.

There are significant challenges replacing VMware Server with ESXi or VMware Player.