--- General purpose ---
I like Dewey Decimal. That's not a person, but, of course, if you were a librarian, you'd know this. I was a librarian assistant in the 70s....twice! I worked at both the Sylvester Public Library in Sylvester, Georgia and the Ralph Brown Draughon Research Library in Auburn, Alabama. Neither were particularly dangerous unless you want to consider paper cuts and dust inhalation as dangerous.
But I dealt with the Dewey Decimal code in Sylvester and the Library of Congress code in Auburn. Those are the two most popular library coding systems in the United States. Dewey Decimal is the simpler of the two and is easily remembered and navigated. It has only 10 top categories: 000 Generalities, 100 Philosophy and Psychology, 200 Religion, 300 Social Sciences, 400 Language, 500 Theoretical Sciences, 600 Applied Sciences, 700 Arts, 800 Literature, and 900 History. The Library of Congress codes, on the other hand, have 21 top categories designated by letters.
The major disadvantage of Dewey Decimal in my opinion is that it is strongly biased toward Western thought. For instance, 200 is primarily about monotheism in general and Christianity in specific. If you want to know something about, say, Buddhism, you have to plumb the depths of the 290s. Little of the 100s is dedicated to Eastern philosophy and most of the Language, Arts, Literature, and History categories is about the parts of the world with European beginnings.
Nevertheless, the Dewey Decimal System is still quite popular and, if you keep the biases in mind, can be quite useful. I use it a lot in planning and organizing my adventures. As for my scientific recreation and lifelong learning excursions, I have a few specific subjects that I'm working with (see the LabBooks at the Therian Timeline), but, otherwise, I have a spreadsheet that will pop out a random subject from a list of Dewey Decimal topics. It keeps me honest. I intentionally choose topics that I would normally downplay.
For this blog, I am being more cyclic. The first articles will be general information about my adventuring. Soon I will do some peoplewatching. And so on through the top categories, sampling from each as I go. Then I will start back at 000 and take another flyby.
I don't expect to live long enough to look at everything.....but I can try!