Yahoo engineer and blogger Jeremy Zawodny has captured a screen shot of a Google promotion page that looks strikingly similar to a Yahoo page in text, layout and design. The pages promote Internet Explorer 7 optimized for the Yahoo and Google search sites. Later, Zawodny notes that the Google page appeared to be modified so as to not look so much like Yahoo's.
No official comment back from Google yet, but Matt Cutts of Google shows examples on his blog of Yahoo search page interface changes in the past that mirrored Google's page, such as with the text and background colors for sponsored links. Several comments to that posting note that Google "borrowed" the pay-per-click ad model from Overture. Isn't imitation the ultimate form of flattery?