Heard about it? If not then I'm guessing you don't use the "interweb" thingy that much, and I'm wondering how you even got here to read this at all?!
When I first started using Facebook a couple of years ago I was told it was just like Bebo, only it's for grown ups. Recently I've heard the same analogy being used for twitter- it's like Facebook, only for adults! Which certainly has a ring of truth to it.
Twitter is a micro blogging tool that allows users to answer (in 140 characters or less) the questions "What are you doing?"
What's the point in that? You may well ask, and if you did ask, my answer would be:
It helps people to feel connected to you, we have an innate desire to make social connections; we like to make friends with people. How we make friends is usually determined on common interests, and so it is also in twitterland.
On twitter you can choose to follow someone's tweets, or unfollow them if you find you're not interested, or you're sick of spam tweets (Yes it happens even in the Utopia of twitterland).
So what use is having tweeps (people) following me?
It increases your brand awareness- within 2 weeks of me actively using my twitter accound I'd increased webtraffic by 120%
As the saying goes- people buy from people not from businesses- if they like you they'll continue to follow you, you'll have interactions, you'll build twitter friendships, you'll get to build your own twitter network of friends.