There was an article about Flicker's mentality on "we don't branch" a few weeks ago: <a href="http://code.flickr.com/blog/2009/12/02/flipping-out/" rel="nofollow">http://code.flickr.com/blog/2009/12/02/flipping-out/</a><p>From the outside it sounds like it would be a nightmare to manage. How could you sanely test all the permutations of "Feature X on, Feature Y off, Feature Z = 4"?