Chris I agree its something that should be sorted in group - I have also asked for some sort of method for posts/threads in groups getting attention but so far I think there is no codes setup for such a notice - something you could look into though and talk to the site owners about as well in that mod section.
Also afew ideas/points to raise with your group
1) Threads - my original idea was that each person each week could post a thread (in any correct section) on the normal side of the forum and then in a master thread in the social group post the link to that thread. Then the members can come and focus on that photo - comment and talk whilst still leaving the field open for the rest of the community to take part as well.
This is working very well with group 1. Heck, I'd be posting a thread per week anyhow, no? Also, we discussed labeling our threads "group x" when posting, but felt it wasn't needed, and might discourage regular members posting in the thread.
2) I think I would advoid having everything in one thread per week - I know its nice and easy in some ways, but it means your going to get conversations going on which are crossing over each other - give that a few posts and the thread would be a nightmare to read through
One thread per week for everyones photos would be a shambles.
3) I never envisioned topics per week - again something to speak to group about I think and come to an agreement. Heck you could all swap msn addresses if you wanted and have a quicker talk in msns chat feature rather than through the forums if you were all on at the same time *I would suggest the sites chat feature, but I think in the changeover and upgrade we have lost this now*
I don't think anyone is having a problem reading the Social Group posts.
You can subscribe to threads there and get an email when someone responds, and also just bookmark your group. Easy Peasy. As far as "topics" per week, if you mean themes, that has totally been elected by the group. If we do a techincal skill, we research it, and then post photos using it.