When installing a new Windows 2008 server or upgrading an existing server to Windows 2008, the Computer Browser service is set to disabled by default.

If you upgrade the Domain Controller that is assigned the PDC FSMO role or you move that role to a Windows 2008 DC, you may see the domain wide NetBIOS-based network browse list get smaller and remote subnet machines will disappear from the list. Eventually you may only see computers from the local subnet in the network browse list. If you have subnets with only one server and it is Windows 2008, then you may also see inconsistent local subnet browse lists due to clients taking a master browser role and they may be rebooted, turned off, etc.

You may see a combination of all local computers on a subnet and some remote computers on a subnet if you have IPv6 deployed and LLTD is being used with Network Discovery to build a network browse list, using Vista clients and Windows 2008 servers. To see if that is the case, you can use the "net view" command or the browstat.exe tool to see just the NetBIOS-based browse list.