"The social problems are straightforward, there is little incentive for competing social software applications to make it easy for people to migrate away from their service. There is no business incentive for Friendster to make it easy to export your social network to Orkut or for eBay to make it easy to export your sales history and reputation to Yahoo! Auctions.
[…] The value of a user’s social network and social information is the currency of a lot of online services. This is one of the reasons efforts like Microsoft’s Hailstorm was shunned by vendors. The biggest value users get out of services like eBay and Amazon is that they remember information about the user such as how many successful sales they’ve made or their favorite kinds of music. Users return to such services because of the value of the social network around the service (Amazon reviews, eBay sales feedback, etc) and accumulated information about the user that they hold. Hailstorm aimed to place a middleman between the user and the vendors with Microsoft as the broker. Even though this might have turned out to be better for users, it was definitely bad for the various online vendors and they rejected the idea. […]
The fact of the matter is that we still don’t know how to value social currency in any sort of objective way. […] The fact is that there is no objective value for reputation, it is all context and situation specific. Even for similar applications, differences in how certain data is treated can make interoperability difficult."
Dare then explains that if it’s not going to happen at the industry-wide level, at least there’s some level of integration done within MSN to re-use a master contact list across several applications.