You may have read the following article:
This claims that Sitecore and Telligent have integrated to make a convenient solution combining the power of a social networking/collaboration platform with the flexibility of a CMS system.
There is a fairly complicated white-paper that has been published by Sitecore which is split into two parts:
- Security Integration
- Content management integration
This solution is not as straight forward as it sounds and it is very poorly supported . . . . I strongly suggest that you do not waste your time heading down this path if you can avoid it. It provides a way for you to use community functionality within a Sitecore site (not the other way around . . . in case you were thinking about pulling Sitecore content into a community site). The solution is out dated and will not work with the latest versions of Sitecore.
We needed to Drive a Community server site and pull Content + Media out of Sitecore which will be used within Telligent community server via Widgets. We also embedded content from Sitecore directly into some of the community theme aspx files. The Community server web site also needed the ability to upload media items directly into Sitecore.
I found that the best method to pull out content from Sitecore into another web application is via a Web Service or potentially a REST service which will run within the Sitecore web application. This will give you the access required to Update/Create Sitecore content via a separate web application.
Posted by richdias 
