This Wiki has has multiple Homepages because it's for creating new Wikis. A Scratch Wiki Home for each language and a About/Test Scratch Wiki Home for each languages community creating that Wiki. See the FAQ for more information.
Block categories are the way blocks are sorted in Scratch's block palette. Blocks are categorized based on their functionality, and blocks within the same category share the same color.
The Scratch Wiki is a free, collaboratively-written wiki that provides information about the Scratch programming language and its website, history, and phenomena surrounding it. The wiki is supported by the Scratch Team, but is primarily written by Scratchers. The Scratch Wiki is a popular source of information for scripts and tutorials, and it continues to grow as Scratchers use it as their primary source of information.
For German-speakers, there is the DACH-Scratch Wiki, available here. It is run separately from the English wiki. It currently has over 520 articles. There are also other, smaller wikis.
