Here is an interesting comparison of Cortana over the course of the 4 halo games:
PTesh adds his dulcet prepubescent tones over the top of one of the new trailers for weapons...
Try upgrading your browser to Google chrome (you wont regret it). There is probably an IE...
Why am I here?
Level: Beaver Creek
On beaver creek if you go up up the ramp to the left side of the blue base you will see a rock that is loose. You can knock that rock down the bottom of the level and read the words underneath which are "Why am I here?". This is a nod to Rooster Teeth's "Red vs Blue" series. The first episode is called "Why are we here?".