· Spreadsheets: Click the "#" next to a playlist to see it as a spreadsheet. Click a spreadsheet column-heading to sort by that metric, click again to reverse it. For rate-limiting reasons, this is only available for small playlists.

· Playlist copying: Click the "±" next to a playlist to make a copy of it.

· *searchlist: If you don't have a playlist called *searchlist, click here. This will give you a song-search widget that works by pouring its results into that playlist, after which you can play or manipulate it like any other playlist. There are also a few special searches you can do, of the form {20 new} or {21-40 mine}, to get the first X somethings, or a particular range of them. The somethings can be "new" for New Releases, "mine" for your most-played albums, "queue" for your Play Later queue, "top albums" for the Rdio Top Albums chart, "top" for the Rdio Top Tracks chart, or "random" for the entire Rdio library on shuffle-play.

· Other people's playlists: To play with any other playlist, paste its Share URL into the *searchlist box and hit Enter.

· Album groups: Consecutive playlist tracks from the same album are grouped together. Click the ↑ to move a whole group to the top of the playlist, the + to add the whole group to your Rdio collection, or the x to remove the whole group from the playlist. Click the ↕ to select a group to move, and then click any other track index to insert the group at that point. (You can gather up multiple groups of tracks by clicking on their ↕s in order, and then insert them all at once.)

· Artist catalogs: If you click an album name, the *searchlist will be reloaded with that album's artist's complete catalog in reverse-chronological order.

· Fixing unavailable songs: If a playlist has unavailable songs, Supercollector will check to see if they can be replaced with available duplicates or potential equivalents. If any of these repairs are possible, you'll get a "fix" button at the bottom of the list.

· Navigation shortcuts: Left and right arrows jump from song to song. p pauses and plays. f finds the currently playing song on the page. The title of the currently-playing song also acts as a scrubber, so click anywhere in the title to jump to the corresponding relative position in the song.

· Bookmarking: While it's open, Supercollector keeps track of where you are in each playlist, and resumes there if you switch back to one you were in the middle of before. The page URL is also auto-updated to reflect the current playlist, position and reference list, so you can bookmark a particular working state if you wish.

· Support: I built and tested this in Safari and Chrome on Macs and iPads. I make no claim that it will work in any other environment. I'm happy to hear feedback, complaints, suggestions and requests, but I don't promise to do anything about them unless they seem irresistibly fun.