I have been Googling a problem that I have with trying to integrate the web application that I am working on with SharePoint 2010. The web application is a wiki style tool that allows users to log in via forms authentication or WIA against Active Directory and create content for themselves and others. What we would like to do is to allow a user have a page with the content they have created in our web application mixed in with content that they have living on the SharePoint server. For example, they may want to see a list of documents that they have on the SharePoint server mixed in with some of their content. To accomplish this, we would like to take the credentials the user has logged into our web application with (for example MYDOMAIN\jsmith) and be able to query SharePoint for the documents of that same user (MYDOMAIN\jsmith) WITHOUT the user being prompted to re-enter their credentials to access the SharePoint server (we are trying to avoid the double-hop problem) We have come up with some options for how we want to do this, but we are unsure of what the best approach is. For example, we could - Have a global user, shared by all users to get information we need from SharePoint. The downside is that we cannot filter SharePoint content to a particular user - We could store the users credentials when they log in, but that would only work for users authenticating via forms auth and would be a security issue that some users/clients would not like - Writing a SharePoint extension using WCF to allow us to access the information we need, however we'd still have the issue of figuring out how to impersonate the user we want. Neither of these options are ideal and in our investigation we came across the Claims Authentication/STS option which seems like it is trying to solve the problem we are having. So my question is, based on what I have written, is Claims/STS the best approach for us? We have not been able to find much direction on how to use this method to call into SharePoint from a Web Application and pass along the existing credentials. Does anyone have any experience with any of these issues?