Probably the most notable addition is the Recommendation engine, which replaces the Tips tab. This can show places that are popular right now, or that have been with your friends, or places you have been to before. It is possible that as the recommendation engine kicks in, Foursquare may just fill a niche in real time and in the real world that others have not yet found the solution to.
With 35,000 new users each day, Foursquare is also introducing new merchant offers, which should be of interest to any business looking to gain footfall. It will definitely be keeping an eye on these as they are rolled out over the coming days and months.
Flash Special (first x number of people to arrive after a specific time) and Swarm Specials (x number of people on the premises for a discount or special) could prove extremely useful at bringing in customers during quiet times.
Points have also been re-introduced which should encourage the competitive nature of those who like such apps. There will be 30 different triggers to gain points, and it will be down to merchants and venues to understand these triggers to make best use of them.
It is still surprising how few rural vendors, shops and merchants are using Foursquare to stand out from the crowd. If you are the only merchant to show in Foursquare when someone checks in, you are likely to attract customers, especially if you have a Special running that piques curiosity. In addition, every check in is shown on the Foursquare website giving you an additional promotional opportunity, albeit brief.