I was unable to get this set up as a drop-option, but a plugin has been added. Now if you go to:

1. User CP
2. Settings & Options/Edit Options
3. At the very bottom, under "Miscellaneous Options" you can highlight each sub-forum that you do NOT want included under "New Posts". So baseball fans, you can eliminate all the hockey stuff, for example.

Sorry to put the onus of this on you, the user, but could not find any other way to set this up. I'll try to spread the word on these instructions in a few places.

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DobberHockey Rules
14 Team Keeper, points only, best 12 skaters 2 dman 2 G count. Playoffs count.
F - Crosby, C.Smith, Wheeler, Parenteau, Hudler, Clowe, Grabovski, Atkinson, Frolik, S. Kostitsyn, Marchand, Peverley, Tavares, Read, Brouwer, Bickell, Gionta, Setoguchi
G - Anderson, Hiller, Markstrom, Brodeur
D - Letang, Del Zotto, I. White, Kronwall, Brodin, Nikitin