My build server is generally empty too. The only regulars I have all came from a friends server where I played. There are about eight of us, weve known eachother for about a year. The whole reason I bought a server was our previous server went down. After about a month I decided that I needed to pick up the slack and buy one. Very few new people end up regulars. For whatever reason we seem to get a lot of noobs and Rpers. The server being strict build with the occasional killing zombies/eachother with what we built, there isnt any tolerance for RP. We’re all very experianced with Wire and Expression 2, not very many new players stick around. Since my server opened (July), our group gained no more then 2 or 3 regular members. I think the fact is, its a slow process. A lot of people will come, not very many will stick around. However, eventually someone will. It just doesnt happen very quickly. For speeding the process, I suggest using a map other then flatgrass, though one that is still practical, as your primary map, and then have a large repetuar of other maps to change to. I would also suggest that you set the name of the server to something eye catching. Standard tags are easy to overlook. Even then, the process is slow. As I stated, my regular group consists of about eight people. That group accumulated over a period of a year and a half. It just doesnt happen very quickly. In my experiance, build servers become very close knit. Thus out of my eight regulars, I have 5 admins and 2 owners besides myself(by rank anyway).
I wish you the best of luck in your build server. They can be quite rewarding.