Why do we require MSN servers to help out with Yodlee accounts?

It's partly historical, partly technical, and partly motivated by security concerns.

MSN Money first implemented Yodlee aggregation for synchronization data on the web site, and MS Money independently synchronized with the MSN Money data store. So, the simplest implementation at the time was to hook those two pieces together.

Of course, the fact that Yodlee at the time didn't have a system to supply aggregated data to client desktops was a factor in our design as well. It simply wouldn't have been possible to implement aggregation via Yodlee without connecting to an intermediate server. (I am not aware that things have changed.)

Not only was Yodlee's design well informed by security concerns, but this overall design does have one additional desirable attribute. Your bank login information is not stored on MSN Servers, and in fact it is not even passed through during synchronization; Yodlee holds on to that privately and securely.

-Russ Paul-Jones
MS Money Product Unit Manager