I recently received a project that contains multiple web applications with no MVC structure. For starters I've created a library (DLL) that will contain the main Business Logic. The problem is with Caching - If I use the current web context cache object than I might end up with duplicate caching (as the web context will be different for every application).

I'm currently thinking about implementing a simple caching mechanism with a singleton pattern that will allow the different web sites (aka different application domains) to share their "caching wisdom".

I'd like to know what is the best way to solve this problem.