MMXI Meaning?

What is the meaning of MMXI or GMMXIE?
Today when I opened my browser I noticed that the google homepage says GMMXIE. The letters MMXI are in yellow and there are a lots of fireworks behind so it's apparently related to the New Year 2011.

They look like roman numbers I used to learn at school, I forgot all about them.
What is exactly the meaning of the MMXI letters in the doodle? Is it some sort of hidden message we're supposed to figure out?

It's MMXI, which is 2011 in roman numerals.

M is the Roman numeral for 1000, so MM is the numeral for 2000.
X is the numeral for 10, and I is for 1, so by adding X and I (10 and 1) you come up with 11.
MMXI is the numeral for 2011.

Basically, Google combined the Roman Numeral equivalent of 2011 (MMXI) with the first and last letters of the company's name.

Google wanted to do something clever for New Years Eve, as they have often done for such occasions.