I'm just following you from @identi.ca... And I can transparently comment on this post you made from your @1realtime.net account.
Identi.ca and 1realtime.net are just two of many Pump.io servers, and they are federated, which means they can talk to each other. Just like you can send an e-mail from a @gmail.com account to an @hotmail.com account, you can follow people on any other public Pump.io server.
Also, as a former user of identi.ca (and apparently, still using it in parallel with 1realtime.net), you should read this: