The bulk of my articles will probably continue to be on the subjects of Mathematics and Subversion and are marked with those categories.
I have tried to keep to purely technical matters. Occasionally I might express an opinion or a personal preference; I try to mark such material with the category Subjective. When I write about software or documents that I think are useful, these are instead marked with References.
Much of what I write is a clarification or re-organisation of well-known material. When I have written about something new, however trivial or otherwise, I have used the Research category; it is unlikely that this material is ground-breaking or previously unknown, but it is original to me.
When an post is intended to be a memory aid, or a method to help check a half-remembered fact or formula, I use the Mnemonics category.
The Example category is used for posts containing only a worked example, perhaps with a link to another post.
When an article contains a query regarding something about which I have not been able to find out, or a problem that I have only been able partially to solve, then it is marked with the Question / Unsolved category.
Many of my categories have finer subcategories. (I may not break Mathematics into further subcategories, as much of what I write about is algebraic, combinatorial or other formal manipulation.)
Some of my categories are rather broad. For example, I just lump Astronomy in with Cosmology.