Every time app.net is mentioned, I see identi.ca/status.net mentioned, yet I know no one using that platform. Rather than just asking how things compare, can anyone present/offer insight into who/how many people are using identi.ca/status.net?

There is certainly overlap, but asking about comparisons or why isn't something used without providing examples as to why they should be used doesn't help those of us not wholly familiar with them.