After using Intersect for a week, I really like the site, and I think its very useful for business to use to help promote their brand.
To me, Intersect is a lot like foursquare in that you kind of check in, however with intersect its more of a blog where you can write full stories. In foursquare you can only have 140 characters. Checking In is a really new and upcoming thing that even facebook has started to use inside the site.
The one thing I like about Intersect is that you can upload pictures, like you can on foursquare – I think it would be a really cool think to use intersect for a month or so, and see where you go on a regular basis and actually be able to see your life in that perspective.
Businesses could also use Intersect like foursquare, and offer a certain reward, or incentive for “checking in” at their business, store, restaurant.