This is probably relevant to the discussion (regarding the LFG addon, and “social networks” created by addons).
Specifically:
It’s difficult to articulate a clear-cut rule for exactly when an add-on crosses the line. However, when an add-on goes beyond presenting information or providing aesthetic customization, and attempts to create an interconnected social network that relies on other players also using that same add-on, we are likely to scrutinize it particularly closely.
I’m not weighing in one way or another, just adding this for insight into what blizzard may allow.