When Marissa Mayer, a former vice president at Google, became the CEO of Yahoo on July 12, 2012, many thought it would be the greatest mistake of her career. Taking a beleaguered company like Yahoo! and transforming it into something that could compete with the likes of Facebook and Google seemed like too tall an order for someone who had no experience running a company. However, in the 10 months she's been in charge, Marissa has worked tirelessly to change not only the image of Yahoo!, but also the inner workings. 

Mayer's latest acquisition was announced Monday morning. Yahoo bought Tumblr for a reported $1.1 billion. It's too soon to tell if this was a good idea or a bad one, but we do know we're not completely surprised. Mayer and Yahoo have been on a tear as of late, picking up a bunch of smart, interesting, startups dealing in a wide range of areas. So, as Mayer proceeds in trying to put numbers on the board, take a look at what she's been up to over the past 10 months.