They've acquired a few products by buying them in, e.g. Blogger, but have also created many of their own innovations. The best known example is GMail. I signed up for that to see what it was like. It's pretty good, but I'm just using my 2GB for extra storage just now.
Today I read that they have added the facility to personalise your Google page with news headlines etc. This is quite neat as it integrates GMail more. For many years I have had a home page at Yahoo! that did something similar. If Google could add some cartoon strips I may have to change my browser home page.