New Avengers, Secret Avengers AND Dark Avengers!?

Can someone tell me why and how these teams still exist when Siege is over(Dark Avengers), the Civil War is over(Secret Avengers) and the point of New Avengers since the original Avengers team got back together? It confuses me every week when I see a new issue for each of em.

All the books are evolved so they are not the same as they were before. 
New Avengers are now the Illuminati book but they keep the New Avengers name I'm assuming to sell books. 
Dark Avengers are a team of villains that were working going on missions for time off of their sentence but they got lost in another universe.  The book is coming to an end though from what I hear. 
Secret Avengers have evolved into what we originally thought they were going to be. A covert black ops team working for shield to handle dirty missions that heroes wont do and the public cant know about.