synesthesia
A social music journal
Synesthesia lets you take notes on songs. You can use #tags in these notes, to help organize your music. You can also @mention other songs, to highlight similarities or differences between them.
You can sort your notes by tags, or combinations of tags. This is handy for curating specific vibes: if you want to find all songs that have a nice guitar solo, that also have a nice bassline, that remind you of summer, for example.
If you are an musician, it is also handy for organizing your inspiration, and songs you might want to transcribe.
Synesthesia is in early alpha. Soon, you will be able to follow your friends, so you can see their notes on songs, and browse their tags.
For the time, enjoy some exploding TVs. I drew these in college and haven't had a chance to use them until now. I don't really know what they have to do with music, but they seem to fit the general vibe.