Currently the addon will update the forum with characters from all guilds on the Roster. Is there anyone who particularly wants single guild support? If not I'll just remove the option.

I say yes because I think removing functionality is a bad thing, unless you absolutely have to

I agree with zanix plus who knows maybe one day I'll use the feature

I haven't exactly removed the functionality as it never existed - it does in SMFSync but not in phpBBSync. Ah well, it probably won't be too much trouble to add it in.