I don't think the 'server' tag serves any purpose at all on a site that's all about servers.  Might as well have a 'Programming' tag on StackOverflow.

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Perhaps it would be better to have tags linux-server, windows-server, linux-client, windows-client and so on.  A question about problems with windows clients connecting to a linux samba server could then be given the appropriate tags, and the part with -server would actually be useful.