Auto open preferred service
I like this idea but I think it could be even more useful if users could set a preferred music service, and when they click the Match Audio link, they automatically get redirected to their preferred service.
If you want to make it clear they were hitting Match Audio, you could even have a "You will be redirected in a few seconds..." page where they can get more information.
Probably the preferred service would be stored as a long-term cookie.
If this idea is popular, I may be willing to implement it and submit a PR.
If this was combined with a button in Chrome/Firefox to easily get a Match Audio link, this could really become a very easy, quick service. (Click the button to get a share-able link, users click and get music at their preferred service transparently.)
I think that assumes great matching all the time. I want to improve that to the point that bad matches are infrequent or correctable by the sharer. I'll leave this open as an enhancement to get to soon, but not now.
Extensions are a great suggestion. It should be possible to use the existing libraries in lib/services to check for url matches and, for example, change the colour of the extension icon when it can be used.
Good point. Missed matches are easily dealt with but incorrect matches are presumably more difficult. If you went with the "You will be redirect in (x) seconds..." method though, you could also display the source's title and artist, such that the user knows what they should be redirected to.