I'm currently pondering whether the new server-side capability of Excel 2007 could radically change the face of many financial application.  Excel is so widely used in finance that many companies could describe it as their platform.  I'm currently involved in writing a web application for a group who use Excel extensively and I frequently think if we could work more harminously with this spreadsheet we could build the application for much lower cost but equal or higher business value.

In the keynote last night they demonstrated the Windows Compute Cluster Server 2003 running Excel Services to perform Monte Carlo simulations using Microsoft Excel.  Initially I thought this was implausible, imagining the response if someone asked, "Can we set up a cluster server in order to run my Excel spreadsheets?", but on reflection I think this could make a great deal of sense.  Even though I'm suspicious about the efficiency of this kind of solution, viewed from a different perspective I think it could represent great business value. 

It's amazing to think that Windows and Office could lead to a scenario where a front-office trader could write software that can be executed in a cluster - an arena that previously seemed the domain of C++ and hard-core developers.  On the one hand it scares me, since there will be less custom C# development for me to do, but on the other hand I like it a lot since re-writing functionality that Excel already implements takes a long time and doesn't give as big a "bang for the buck".

Obviously I need to do a lot more research on Excel Services.  There's a good introduction here and some more technical details on how you can call Excel through web services.