Fact: Market Snapshot violates most MLS's rules on data usage.
Fact: Other subscribers to MLS data are unable to use the same data in their products currently.
Fact: One of two things is going to happen:
1.) Market Snapshot goes away, or; 2.) Everyone gets access to the data and Market Snapshot's profit margins erode. There are currently about 50 services that could provide a similar product in about a month (or less) if they could get the data... and then they'll fight it out for marketshare. This includes Zillow.
Fact: If data feeds open up, Realtors can kiss thier competitive advantage goodbye.