For someone who is not familiar with it like me, this is very strange indeed. To be honest, I have to refresh the web page several time, suspecting that the logo was not fully loaded. After 2 more reloads with the same logo, I decided to follow the link from the logo. Silly me, it was a Morse Code, which I only heard off and knew nothing more. Apparently, Google is celebrating the 218th birthday of the founder of the code. Samuel Finley Breese Morse (April 27, 1791 – April 2, 1872) was born in Charlestown, Massachusetts. He is an American painter of portraits and historic scenes, the creator of a single wire telegraph system.
If you want to know what the logo is about, try using the codes found here . Even if you don't refer to the codes, you will probably have a good idea what it means. It's a Google website (their main homepage) after all ;)
Surprise, surprise... Not all Google websites will display the logo (at the time of writing this post). I've manage to get this odd-looking logo at these following websites (to list a few):
http://www.google.com.sg
http://www.google.cn
http://www.google.com.au
You can also do a cool online conversion of any text you like in English into Morse Code here. Try converting "Google" first and see its similarity with the logo displayed.
Try copy-paste the code below in the "Convert morse code back into English" on the website and see what it means...
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You can read more here or simply Google the keyword "Samuel Morse" for more online resources.
*All logos and trademarks belong to Google.