In short: Google hid an embedded YouTube video behind its current Google Doodle in celebration of its founding twenty years ago in addition to sharing some new insights into the top searches over those two decades. The video runs for one and a half minutes, showing some of the timely searches for 18 of those years beginning with the questions "what is Google?" and "what will happen on Y2K?" Of course, the compilation wouldn't be complete without queries about whether or not Pluto is still a planet beginning in 2006 or 2013's search for the proper pronunciation of "GIF."
Background: A deeper look at an interactive chart shared alongside the video reveals that some search terms aren't limited to just a year or two. In fact, some searches remained relevant across the entire period including Pokemon, David Beckham, Chevrolet's Corvette, and The Simpsons. Google's timeline covers Actors, Animals, Athletes, Authors, Books, Dog Breeds, Films, Foods, Games, TV shows and a half-dozen other categories highlighting how long specific terms held their own, and other interesting facts about their time at the top. The category for searches performed relating to sports cars, for example, seems to be the most stable of categories covered. The top three spots appear to have been held by the Chevrolet's Corvette and Camaro for the entire period with the two models only swapping positions in mid-2008. The Ford Mustang has held the third slot for that entire period.
On the other hand, the songs category has fluctuated sporadically across the years since Google's conception. Some singles such as Disney's 'Let it Snow' only manage to hang on for a year, while longer-lasting hits like Usher's 'Yeah!' appear and leave the chart before showing up again later. Similar trends exist across each of the categories, showing how pop-culture and media have a heavy influence on how and what people are searching for. Google takes things further still for each item included in its assessment. A click on any of the items on the chart reveals further details about exactly how each term was searched. For example, Mars-related searches now top queries for space objects and are mostly associated with the term "life on Mars" or "mission to Mars."
Impact: Twenty years of search history may be a bit much to share in a single article but this particular Google Doodle and the associated charts ultimately serve a dual purpose. Namely, they both provide real insight into trends, and act as a way to thank users for continuing to use the service. Google has come a long way since starting out as almost exclusively a search company. In either case, tracking world trends and helping users find what they want or need is something Google says it hopes to continue doing for the next twenty years as well.