Hi,
I had the very same problem a couple of weeks ago. If you ask me the databases have been abandoned - I found 3 that could be of use to you:
1. The original one from IBM
not sure where I got that one but it quite old as well - maybe it's the plain vanilla one. I did read somewhere that IBM was open sourcing it but I couldn't find a new version of the DB.
2. xTalk -> last update 2010
http://www.openntf.org/main.nsf/project.xsp?r=project/xTalk%20Discussion%20Forums
3. xPages Forum -> last update 2011
http://forum.openntf.org/main.nsf/project.xsp?r=project/XPages%20Forum/releases/A3A99FE68FAD3DC886257878006F52FD
as you can see its all a bit old which, in turn, makes the users think Notes is stuck in the past.
I have these 3 up and running (well, the xPages forum (no. 3) started looping as soon as it went live (worked perfectly in testing) so I don't really have any info about that forum) - if you find anything else it would be great if you could add it here so that I can also check it out - am currently thinking of going to an Open Source discussion forum :o( Pity that!
Sorry to be the bringer of bad news - maybe somebody else has another Domino option?
Cheers
Ursus