What about classifying businesses according to the Debian guidelines (main, contrib and non-free)?
This would undermine the goal of a Free Software Business and the GNU Business Network. This is also why e.g. Debian is not listed as a recommended GNU/Linux system by the FSF and the GNU project simply because Debian includes non-free software.
And by debian merely not being listed, this subtle fact is hidden from most. Let it have a weaker public listing to make its standing more clear; Let people know it has only 2nd level membership because it includes non-free software.
How about letting people know that it has no membership at all?
If you say `ok, here are businesses we allow in our network', then you are saying in turn `we recommend these businesses and their practises'. If a practise is such that it is OK to support/develop non-free software, then this undermines the whole goal of free software. It doesn't matter if you have a little note saying that they are in category FOO or BAR.
Maybe, but we will be promoting them because of (and in proportion to) the positive and free activities they undertake and not the non-free activities.
But they do non-free activities, thus you are promoting those activities too.
Cheers.