I'd joined Ning as one of the first 23 things but didn't stay active. To complete this Thing I posted a picture of my cat to the Ning and tried posting the Ning badge to my blog, but somehow the code was corrupt or unevenly tagged. Since it's a matter of posting code which I've previously done, I won't try to figure out which code is unbalanced. Because it's another quasi-social networking site, if I were looking for someone in the field, I may look there, but I didn't join any groups or even pursue beginning one.
Sometimes sites are laid out compactly and manage to hide features from me. If a website or network's page changes significantly, I don't plan to invest enough time on them to make them readily updatable or find out where "that thing" went in order to update my information. If I focused on one website where activity was more my style, I'd make it more of a priority to find where "that thing" went to in order to keep it up to date.