Just saw this at 123RF:

Welcome Flickr� Users from all of us at 123RF!
You've uploaded your images to Flickr�, dozens of people have commented how great your shots are, how you have an eye for photography and you know in the back of your mind, you know you could derive some income from it all? Now with 123RF, you can!! With 123RF you can turn your passion into cash! Here's how�

More here: http://www.123rf.com/flickr_intro.php

Indeed, there was a link to it from their main page, now it's gone.  Maybe they made a mistake posting it there too soon?

They made some agreement with Flicker so people can submit their images from Flicker to 123RF.

Regards,
Adelaide

Found the following statement from Alex @ 123RF on another board:

"Hello All,

The fact is, Flickr revoked our Flickr API Commercial key after 2 weeks
of issuing it and within 24 hours of us going live with it. Our
intention is to facilitate the easy transfer of images from Flickr to
123rf for those who have accounts on both sites.

We'll keep you updated if there are any more developments on this front."