A Facebook post from Green Man Gaming follows up on recent questions about the sources of some of the game keys they sell, and allegations that some of these are from the grey market (thanks Eurogamer). They say from now on they will provide customers with pedigree information on all game keys they sell:

You spoke, we listened.

We know you want great games at great prices. In response to your feedback, rolling out from today on the Green Man Gaming store you’ll see our pages now have two new pieces of information:

1/ When you can expect the delivery of a key
2/ The source of that key

We are committed to continually improving our site, so you can expect the very best service and experience from us. Bear with us as we have over 5000 titles to update, but remember that your feedback is always really important to us, and we want to keep helping you make informed decisions when shopping with us. Thanks for your support!