Just checked out your site - it's got a lot of members! Having a look at the blogs (last blog post in late January of this year) and the forums (7 forum topics total) have you considered a Facebook fan page? If people aren't really interacting and are just using it as a source of information, then it might be a better option anyway.
Just an idea. I don't think the announcement is going to change for just one person :)
I think a facebook group or facebook page would be a good option. How you have seen are the members not very active and for me i have to decide that I can forward and continue only one Ning Network. I was developer of http://candle4tibet.ning.com - so I will looking forward what will happen with this network about 6000 members. If it will stay I can forward informations about Tibet by Artists4Tibet on http://candle4tibet.ning.com/group/Artists4Tibet - maybe Ning will not delete this site?!
After I asked to migrate with my network and I downloaded all the content from my network - the URL doesn't exist anymore on NING. It moved now to http://grou.ps/artists4tibet/ but the migration seems not to be ready until now because many photos are missing right now. Thanks to NING to start this small group on NING and provides a migration path. Now I need to know how I can insert all content to this new site.