Flickr makes it so easy to find photos, doesn't it? And if you're blogging for a commercial outlet like this one, or, say, Valleywag, it even makes it easy to find photos licensed for commercial use.
Yesterday, Valleywag disregarded that when it copied and republished a noncommercially licensed Dan Farber photo in its Digg/Federated Media item. (And I don't think it's the first time this has happened.) Valleywag is either confused about how Creative Commons licenses work or just being careless. CC licenses are still so new that few types of enforcement have actually yet been considered by a court. This type has.
I bring it up because blowing by commercial use restrictions in Creative Commons and other licenses is a widespread (and legally loaded) phenomenon. Dan Farber is a gentleman and consummate professional, and I'm sure he has bigger fish to fry than making an issue of this or an example of Valleywag, to whom he's readily granted use permission in the past. (He tells me he would have done it here too.) Regardless, cutting corners like this isn't professional and isn't wise; just ask Niall Kennedy.