Am I eating a free lunch?

For the past several months, I have been using the Blogger service to create this blog. Blogger is a subsidiary of Google, which offers the service for free to the public. Google makes money from its search engine by selling ads, but my blog does not have ads unless I authorize them. I keep waiting for Blogger to offer to sell me some add-on services, but that hasn't happened yet.

What's in it for Google and its shareholders to give me all this free service? I am puzzled. I hope one of the commentators can enlighten me.