If you want more active members, you can try advertising on these forums (all of these forums have their own advertising forum that let you advertise your sites there without breaking the rules).
list of a few
http://z10.invisionfree.com/xgmx/index.php?showforum=102
http://z11.invisionfree.com/explosmertacul…hp?showforum=35
http://z11.invisionfree.com/Planet_Mac/ind…hp?showforum=44
http://trollz.aceboard.com/328389-2392-0-Advertising.htm
http://z6.invisionfree.com/Reenactor/index.php?showforum=478
http://z6.invisionfree.com/PlanetGnome/ind…hp?showforum=54
http://z4.invisionfree.com/My_World_Forums…hp?showforum=38
http://forums.zoomshare.com/viewforum.php?..0Site+Zoomshare
http://www.forumsector.com/forumdisplay.php?s=&forumid=9
http://z14.invisionfree.com/Gaming_Evolved…hp?showforum=20
http://z3.invisionfree.com/Metroid_Headqua…hp?showforum=15
http://www.pokemonworldonline.net/forums/viewforum.php?f=32
http://war2.warcraft.org/forum/viewforum.php?f=12
http://z6.invisionfree.com/RPforum/index.php?showforum=34
http://z6.invisionfree.com/RPforum/index.php?showforum=35
http://z10.invisionfree.com/Star_Central/i…p?showforum=252
http://z6.invisionfree.com/Computer_Talk/i…p?showforum=225
http://z10.invisionfree.com/IGTour/index.php?showforum=61
http://s1.zetaboards.com/Alien_Board/forum/422054/
http://s1.zetaboards.com/The_Schlieffen_Plan/forum/422053/
http://s1.zetaboards.com/rpflashpoint/forum/300910/
http://z7.invisionfree.com/Metroid_Evoluti…hp?showforum=20
http://forums.civfanatics.com/forumdisplay.php?f=25
http://support.aceboard.com/2-6261-102618-…your-forums.htm
http://www.createforum.com/scunite/viewfor…&mforum=scunite