There's thread on stackoverflow about this
https://stackoverflow.com/questions/5524046/is-telerik-extensions-for-asp-net-mvc-free
It says that it is ok for internal site, but I think it is still not clear (also in faq notice about internal site usage is gone I think).
They say, as long as website is internal, you should be ok with open source license, but
1) Can I use it for site, that has closed community, I mean only logged in people will use telerik components?
2) Can I use only for site's administration part, that means that only internal staff will access it?
UPDATE: It looks like same question (same license type) – Using GPL libraries without modification on a commercial website, do I need to make my source code available?, but answers are completely different?
UPDATE2: I don't wish to in any way distribute site's code.
Best Answer
For most situations, AGPL is the only GPL license that requires releasing the source code of hosted web applications. Under vanilla GPLv2, if you're not distributing the modified and compiled binaries to end users you do not need to release the source code. You're not distributing the software, you're allowing remote access to it.