Google celebrated its 13th birthday today, and in that time, it has had a number of product hits and misses. As with any big company, it has also had to contend with a number of PR snafus, from unauthorized data collection to antitrust investigations.

Most recently, Google executive chairman Eric Schmidt was on Capitol Hill defending his company's search tactics. Google does not favor its own products in search results or "cook" its results to give it the upper hand, Schmidt told the Senate Judiciary Committee.

Schmidt made his appearance after the Federal Trade Commission (FTC) confirmed that it was conducting an investigation into Google's business, though it provided no details about what that probe might entail. The EU, however, is also looking into whether Google is abusing its dominant position in search.

Google has also tangled with the Chinese government over censored search results. After allegations of hacks originating in China, Google had to decide if it should serve up uncensored results and risk losing its content provider license in the country. It settled on a hybrid approach. There's also the issue of Street View; it's cool, but is it too invasive?

Here at home, the search giant has been caught up in a controversy over: the unauthorized collection of data traveling over Wi-Fi networks; location-based apps; Android malware; its effort to digitize books; and aggregate the Web's news.

Check out the slideshow above for more details on Google's PR snafus. Can you think of any others? Let us know in the comments.