Do you really need a site anymore?

So, here's a serious question that may seem ridiculous:  Does a typical company need a website anymore?

Seriously.  I've been mulling this over for the past few days.  The root of this little question was planted in my mental dirt when I was thinking about registering a domain - again.  I say again, because I have registered several domains, let them expire when the idea loses steam, and then need to re-register (or often times come up with a new domain name) when the idea is resurrected by a new thought or conversation.

I started to think about the different social platforms companies have identities in the comprise their marketing universe: Facebook, Twitter, now Google Plus, and on and on...  It made me wonder, especially with platforms like Google Plus, do I really, truly need a website anymore?  Of course, it depends on your product/service, but for an awful lot of businesses these days, the answer may actually be "nope."