How do I extract music from song?

What are good ways to take note (software, web app) of the music you fancy?

• Here are my recommendations of such a service: I only need a database app or software, I do not need it to connect to my actual music collection in any way whatsoever. Say, I listen to some streaming service but this is a competitive market so next year I might change to a new service. I want my database to be separate. I am just looking for a cool way to catalogize music I like from streaming service such as Spotify or Rdio, my offline collection, singles, bootlegs unofficial releases (such as ones on YouTube; but I might be too lazy to extract every song out of Youtube I kind of liked and want to listen to again) classics and new discoveries alike. What is a best match for my needs? Edit: I have just learned about http://lifehacker.com/5812986/turntablefm-adds-adorable-characters-to-online-radio-is-an-incredibly-awesome-time-waster It might have been a good start for what I am looking for though I know it does not cover entirely the same description I have sketched up.

• Answer:

  I'd use a simple text file, but since my entire personal computing infrastructure is Unix-based, it's the practical choice. It's infinitely flexible (freeform text = no schema to mangle over time), easily searchable, easily updated (ls newstuff/*.mp3 >> db.txt, then use your favorite text editor to annotate), easily shared even with non-Unix users. That said, I think it's still perfectly workable if you're a Windows user. The key tool you'll need is a good text editor with sufficiently powerful search (e.g. Notepad++).