It largely depends on how impressive you are when you come in, and how in-demand your skillset is across the company. After the hiring decision is made, managers then "bid" on Nooglers they want for their teams, and higher-priority teams (like Android, Ads or Search) will beat out lower-priority teams (like Blogger or Finance). If multiple managers bid on you but you don't like the team you're assigned to, you have the option to work for one of other ones, eg. I was assigned to Search when I joined in 2009, but my recruiter made it clear that if I really didn't want to do it, there were teams in GMail and Docs that would be happy to have me. If only one manager has bid on you, then you're stuck there.