@RobDixonIII:twitter, you don’t have to question me. You can see for yourself by spoofing the user agent header. Compare the code that you receive from Google’s servers. If the user agent contains Opera, there are large parts of code missing or are outdated. You can clearly see that by doing server-side browser sniffing, Google is serving different content for Opera than to the other major browsers.
I can’t say for the many browsers out there, but this happens a lot to Opera. For example, big companies like Amazon and Microsoft also do the same thing and serve Opera different code. Amazon serves Opera missing code that prevents many of the Amazon features like Amazon Cloud, Amazon TV, appstore, etc., from working. The workaround for server-side browser sniffing is to spoof as a different browser so that servers can’t detect Opera from the user agent header. Sadly, spoofing as Firefox is what Opera had to do to bypass Amazon’s server-side browser sniffing.
Historically, Microsoft’s MSN.com sent Opera broken CSS. You can look for Opera’s response by searching for “opera bork bork bork”.