lammert - 2:26 am on Jul 29, 2010 (gmt 0)
There can be many legal reasons to block Internet access from specific states to your site, for example if you offer items on your site which are legal in one state, but illegal in another. Weapons, adult content, alcoholic beverages and gambling come to my mind as potential candidates for this kind of state level blocking.
Another more commercial reason can be if you have two websites, one targeting a single state, the other targeting the rest of the US. But in that case it might be a better solution to redirect visitors from the wrong state to an explanation page, or to the other site directly, rather than just blocking their access.