"The value of a LinkedIn or Upcoming.org is in the aggregation, not using them as an authoring tool or repository for one’s own data. They should focus on competing on the value-add of their aggregation. I don’t see any disadvantage for them in opening up the input mechanism to pull the source information from external authoritative feeds (or support the information being pushed to them).
I’m not ruling out the need for information hosting services. But I think aggregators and hosting services are different beasts and separating them provides many advantages to both providers and consumers of information."