My perspective has always been that facebook is just another website. It could also be said that google is just another search engine. It has risen to prominence as one of the most used tools on the net, and the company behind it, has developed several key new internet technologies - however, it really is just another website. The difference between the two - is how they fundamentally and primarily see the net.
Facebook has been involved in several tethering deals - pinning their website down into cellphones and internet devices, with vendors whose focus is to secure advertising revenue through click through. The concept of open browsing, and an extensible, flexible approach to resources - is alien to them. They have been hard coding links into the phones.
Google, on the other hand, seems to be working to open the device. Droid is a great example of how, when given the chance, google opened the door to many different developers and let the phone go wherever the user wanted it to go.
So, although both google and facebook are really just websites - google tends to capture the essence of the internet as a many to many communications medium - and that vaults it into utility. Facebook continues to attempt to equate connections between two people in terms of a flattened definition of 'friendship' and privacy, and this voids out some of the utility of an open internet approach to community.
Google Plus is a new product being designed by Google, that seems to take an open, flexible approach to social networking. Interestingly, it also points to ways that we categorize and control connections to others around us - the internet still seems to have a largely dangerous effect on meaningful relationships within our first, actual circle. It remains to be seen whether virtual circles from Google Plus, can actually help us to stabilize that circle and strengthen our lives, our communities and ourselves.
Check it out at : http://www.google.com/+