Some further information:
The character was designed by a Singaporean doujin group called Collateral Damage Studios, and was actually released sometime around May.
The character was recently adopted by Microsoft Singapore (not international, AFAIK) - I am not clear on the details and how it happened. Kind of came out of nowhere. There's a theme pack available too, on the circle's website.
So yeah, it's actually still an eastern thing. The animation was apparently produced by the doujin circle together with an animation studio.
Edit:
http://www.collateralds.com/news/random/the-story-of-aizawa-inori/Official statement via Geekwire:
In conjunction with the launch of Internet Explorer (IE) 11 on Windows 8.1 in October, Microsoft Singapore today unveiled Inori Aizawa (藍澤祈), an original anime character whose backstory symbolizes the browser?s transformation into a modern and powerful best-in-class browser. This was a local Microsoft execution in Singapore in conjunction with the Anime Festival Asia (AFA) 2013. As part of the local execution, this is the most extensive collaboration undertaken by the team to reach out to anime and Japanese popular culture lovers across Asia.
and
The anime character was created by Microsoft Singapore for the Anime Festival Asia (AFA) 2013. This is a local marketing program for anime and Japanese popular culture lovers at AFA 2013 and across Asia and does not represent an official mascot for Internet Explorer.