Save Text To File is a Firefox addon which allows you to save the selected text on a web page to a file.
While this sounds very basic, it can save you a lot of time. If you spot something interesting on a web page, you don't have to bookmark it, or save the entire page and try to find the paragraph you need later: just select some text with the mouse, right-click, select Save Text To File > Save, and it's saved to a TXT file in your User folder.
By default these files are named with the date and time, like "HighlightedText--15-03-2015--10-58-28.txt". This helps you group files together and find the snippets you need later.
If that doesn't suit your needs, there are options to use just the date or time, to change the date format, or to simply add your chosen text to a single project file, along with the date and time it was saved, and the source URL.
Version 3.1 (Release Notes):
- Fix windows formatting issue