The free blog hosting service on WordPress.com is great but it does do a few mildly annoying things by default. Thankfully you can make it behave pretty quickly by ticking a few boxes.
I’d been meaning to write a guide to what to do immediately after you set up a WordPress.com blog but now I don’t need to as Chris Unitt has written his own and I agree with it 100%.
Even if you don’t agree with it 100% please turn off the Snap Shots popups and hide Related Posts. They’re distracting and pointless and you don’t need them.