It seems as though the boards will still be around in a different format, linked to Facebook and Twitter.
As one of the few humans on Earth not on Facebook, I don't know how this will effect me. Hopefully, I will still be able to view the discussions there. While I didn't post often on the DC site, I did regularly read the threads.
I hope any displaced Supergirl fans looking for a place to discuss the character will find this blog and feel at home here until the DC boards are back up and running. Welcome aboard!