There are many great SQL Server articles in TechNet WiKi. The easiest way to find them is to check them from the portals such as Transact-SQL Portal, SQL Server Integration Services Portal, SQL Server Reporting Services Portal, SQL Server 2012 Portal. I suggest you to explore these portals and also, in case you come up upon an article which is not yet added to the appropriate portals, go ahead and add it.
In this blog post I want to introduce two recent additions to SQL Server articles in TechNet WiKi which were inspired by the TechNet Guru Competition.
The first article is a very thorough and comprehensive analysis of SQL Server Error Handling mechanism written by Saeid Hasani Structured Error Handling Mechanism in SQL Server 2012. As you know, the structured error handling mechanism in SQL Server was introduced in SQL Server 2005. In SQL Server 2012 one important addition was put into the language - ability to throw the error back to the calling application / procedure. Saeid dives deep into examining the error handling mechanism, what errors can be caught by CATCH statement (as we know, not every error can be properly caught in SQL Server even with the structured error handling). So, this article is a very enjoyable and helpful reading if you want to learn all details about error handling in SQL Server. No surprise, this article won September's TechNet Guru competition in T-SQL section.
This article explains the most important concept in SQL Server about logical order of operations, and that all the work is done on the set. Saeid illustrates the important points of the article with the simple to understand code samples and very nice images.
So, in conclusion, I want to tell that TechNet Guru Contribution brought many great articles to TechNet WiKi and to SQL Server side of it in particular. I hope you'll enjoy these articles as much as I enjoyed reading them.