Friendly or Friend Overload

I recently noticed a friend of mine from one part of my life was friends with someone else I knew from another part of my life.  I was so excited I tagged them and said "Yeah, I feel like I made a connection."  Later I got an email from one of them asking me who the person was she friended which she then explained she accepts everyone that asks. 

This all got me thinking.  Is it a good idea to friend on Twitter, FB, Google+ and any other social media website all those people who request to be your friend?  I know on Twitter unless you're private you have not control and you could find yourself being followed by a squirrel.  But what about the rest. Is it overload? 

As an author with a book coming out in April (I'm counting down) and maybe a short this year, I wonder if liking everyone and knowing everyone in the social media way, does it help your sales?  If I throw my name out there and like everyone and want everyone to like me will it bolster my sales.  Will someone discover a new author?  Or will I feel over-exposed and want to crawl back into my writer hole?

I could ask my friend how it's helping her but like me, hers isn't out until next year as well.  So I'm throwing my question out to the masses.  What do you think?  How do you roll?  Should I like everyone?  Should I stay right where I'm at and be selective with my friendship?

I'd love to hear what you think.