Google has good security practices, can implement those in any big corp as they are very straightforward. Mudge previously worked at Google so I'd assume he was hired to help Twitter security get better by implementing some practices from Google. But maybe he was just hired to look like Twitter cared and they didn't really want to change anything.

Google also has a very good ingrained security culture. They understand that they hold on to people's most private and critical data, and rock-solid security has to be a cornerstone of their business.