Google has confirmed a bug where searchers are forced through a Google redirect page prior to ending up on the ultimate search result. This only happens when you search for something with a hash, for example a search on [c# language].

If you search for that, you are presented with search results, but if you click on the search results, you are prompted by a Google redirect warning. Here is the path:

You can see the warning by clicking here.

I wonder if people who rank well for # related keywords have noticed a major drop off in referrals from Google?

Google confirmed the bug in a Google Web Search Help thread, saying:

Forum discussion at Google Web Search Help.