Assuming you want to reach a very large number of users through the browser, SIlverlight 3 & 4 are Windows only. The Mono implementation, Moonlight, is only Silverlight 2 compliant.

>Hello,
>
>We are still using mostly VFP for business applications, but we are planning to move very soon to .NET with C#, WPF and Silverlight to create applications that will be working in a browser (web applications). There are some questions I still have, like:
>
>1) Would you consider Silverlight a valid tool to build UI for serious business applications? I see it mostly used in scenarious where you previouly would have seen a flash application (like multi media, galleries, music/video etc).
>2) Moving from Deskop to web applications, how can we address security issues that will certainly come up with this technology? Previously we haven't put much thought about that, but having an application accessible from a web browser on some public IP will have some clients be worried about how to prevent unauthorized persons access their applications and their data.
>3) And why is there no "Silverlight" category on UT?
>
>Do you have any comments about this, I would be very thankful to hear your opinion about this.