Changes in the listing price
Any changes are displayed not only in the information for a listing but also directly on the map. A small red arrow point down indicates a price reduction. (For the other way around, it's a green arrow upwards.) There is also a list on the start page with the largest price changes during the day.
Number of days on the market
Another type of information that isn't shown on any other listing service is the number of days a listing has been on the market. This is displayed on the listing and could also be used as a search parameter.
The site is run by a company called Boliga Sverige Aps but behind the service is the Danish company Boliga.dk, which started in Denmark in January 2007. Their start in Denmark was controversial creating an upset among the brokers. Read more here (the Boligan site), here (Swedish article) and here (Danish article). However, they have also won the prize for best new website in Denmark.
Impressive mapping functionality
From a technical standpoint, what impresses me most is the mapping functionality. Especially the way to browse without need to first make a choice of municipality. Brilliant when you looking in an area where you're unaware of the boundaries of the municipalities (or states for that reason).
The market for listings are heating up
This is the third large listing service that has entered the market in less than 10 months! It will be most interesting to see where the market is going.