Tumblr MP3 Player
One of the most frequently mentioned gripes with Tumblr’s audio post functionality is the lack of a continuous playlist of audio posts. Various people have attempted to hack workarounds (myself included, with limited success), but none come close to what Dan Kantor has managed.
Dan’s solution is powered by Streampad and appears as a narrow strip across the bottom of the browser window. It works well but suffers from a common problem with playlist-style players: if you navigate away from the page on which the music is playing — even to another page on the same tumblelog — the music stops and must be played again, from the start. A useful addition might be to open it in a dreaded popup window rather than playing it in-page.