Kayak v. Bing

Click for bigger comparison. Story from Wired. The story mentions possible copyright claims, but not trade dress, which seems odd given that the story also quotes multiple reviews noting the similarity between Bing and Kayak, including one person who simply assumed that Bing had licensed Kayak's technology. Query: do you need to make more changes to design around a copyright claim, or a trade dress claim? My money's on trade dress, actually. (Disclosure: I'm a Kayak user and like it; I think the Bing result shown is highly similar to Kayak, but I also think Kayak's design has a lot of attractive functional features, so I have yet to form an opinion about the viability of any legal claim.)