My reasons, in no particular order.
It allows me to keep a general eye on what is happening in the world of design. This, and a few other blogs (see recent “which blogs do you visit” thread) are now my default resource for general design awareness. I then add relevant sites to my Chrome bookmarks which are synced and over-anally archived over my home and work computers!
As mentioned by a previous poster, there are only a few sites I surf for pleasure, so if one of them is related to my job, and therefore my pay-cheque, then great!
I love debate and discussion of any kind, so design-centred ones are of particular interest.
I love seeing other people’s work, and it inspiring mine, and me, to constantly aim for a higher level.
I like being able to feedback on people’s work when asked. I also enjoy feedback on mine.