Hi! I used to work at Pandora and was just searching for solutions because I'm having a similar issue with connecting to Last.fm. Wanted to jump in here for a few reasons: To clarify what I think OP wanted, to offer up my current hack if they want to try it, and to reiterate that this is a feature I also would love and have seen other requests for (mostly on Reddit).
That other thread isn't quite the same request, though any public API might be a step in the right direction. While importing and exporting playlists between services is a common request, there are some 3rd party tools that accomplish that fairly well. What's different about the Last.fm request is their concept of 'scrobbles'. It records every track you listen to with precise timestamps. That's what they're talking about with listening history. There's direct connectivity to Spotify and other apps through their APIs to get accurate data, and also a ton of fan-made scrobblers e.g. a shazam-like one to listen to music playing near you. But they have their limitations and I've found it pretty hard to get my Pandora spins to count so far, especially on iOS and the Mac desktop app. So it would be great if there was support to connect your Pandora account directly to Last.fm and send each song to them as it spins. Or even just bring it up as a hackathon idea to get a better scrobbler for Pandora specifically.
If OP or anyone else sees this, my current solution when I can play Pandora through speakers instead of headphones is to use Finale (iOS app) in 'listen continuously' mode. It picks up sounds every minute or so and attempts to match it to a track. You can also scrobble manually (e.g. if it misses something or you're using headphones).
