I think the biggest thing that puts this in a different category than distributed computing projects like Seti@home is that with Seti@home, you use a package which includes all the software used for the analysis, then simply exchange uninterpreted data, and the results from it back and forth. With GriPhyN, scientists send both the data and the code for the analysis program. The potential impact this could have not just on computing, but on open source style projects is incredible!