Guessing the brands here is quite difficult, because the color samples have come from many different sectors. I don't think many people would be able to differentiate between the blues for LinkedIn and AT&T, or the magentas for Flickr and T-Mobile. However, if you showed me a blue sample and pink sample and told me they only represented social media sites - or mobile telecoms companies - then I sure as hell could tell you which one each is.<p>As a guessing game, I really liked "Unevolved Brands", where logos were reduced to circles and solid colors:<p><a href="http://www.flickr.com/photos/grahamsblog/sets/72157625155090078/" rel="nofollow">http://www.flickr.com/photos/grahamsblog/sets/72157625155090...</a><p><a href="http://unevolvedbrands.tumblr.com/" rel="nofollow">http://unevolvedbrands.tumblr.com/</a>
Also check out <a href="http://kashiwasato.com/" rel="nofollow">http://kashiwasato.com/</a> web site of one of Japan's top designers.. Very conscious use of simple color palettes for striking branding. (Warning: site is heavy on flash and noisy..)
Interesting to see that UPS stand out from the crowd. They chose that color because it looks professional and dignified, but I'm sure there is some benefit from not looking like the rest of the blue corporations.