If you have ever had the chance to browse through the Usenet newsgroups, you'll find an incredible resource of posts on a variety of technical topics, including just about every imaginable facet of .NET development.
Google Groups is a web-based Usenet browsing application that lets you read and search through the Usenet posts. Before Google went to their "beta" version of Google Groups, you could narrow your search focus down to a particular group, or subset of groups, to return results matching a particular topic area.
For example, if you wanted to search only Usenet posts that were .NET related, you could enter a search query using the "group" operator like:
Control.Invoke Control.BeginInvoke group:microsoft.public.dotnet.*
If you wanted to further narrow your search scope to just the Windows Forms newsgroups, you would change your group operator like so:
Control.Invoke Control.BeginInvoke group:microsoft.public.dotnet.framework.windowsforms.*
You can also easily explore the newsgroup hierarchies by just entering the group operator and no search terms and then clicking through the links that are displayed.
Unfortunately, with the latest version of Google Groups they have dropped the functionality that lets you search like this. I've sent numerous feedback suggestions asking them to either restore the old functionality or provide a similar means of searching, but so far I've had no response. Feel free to send them your thoughts, too.
Until Google restores this functionaly, you can access the older version of Google Groups by pointing your browser to a different language homepage:
http://groups.google.es/grphp?hl=en or to a subset of groups like http://groups.google.es/groups?q=microsoft.public.dotnet.*&hl=en
In addition, I also like to set up several hotkeys using WinKey to automatically open up FireFox and take me directly to a pre-defined newsgroup. Once there, I just check the "Search only in xxxxxx" radio button and click Search and find all the results filtered to my specific topic area. This saves me from finding my shortcut to launch the browser, navigate to the groups, and enter my query. Definitely a time saver for those who love shortcuts!
Read: Using advanced search techniques with Google Groups