DC'S NEW 52...Does it throw out all continuity prior?

I absolutely loved the new 52 by DC. Action Comics # 1 was the best single issue I had read since I first encountered Daredevil during the Frank Miller years.

But...does this throw out all the continuity prior to it? Are the Crisis series still relevant at all? I know Batman and Martian Man-hunter are alive. Is that because of Blackest Night? I dunno...it seems a lot of great stuff by Geoff Johns and Grant Morrison is thrown out.

Help me understand what's relevant and continuous and what's not.

Thanks.

Most of GL's continuity is still in tact and about 65% of Batman's. Everything else has pretty well gone the way of the buffalo.

I think so. Its a completely new start. But some things from pre 52 still happened like Batman and Red Hood.

Batwoman is completely unchanged as far as I can see.