I have long wanted an online database that is accessible from anywhere, including my "dumb" cellphone - voice response would be ideal - for when I'm out thrifting. When I run across an LP that looks interesting, it would be great to look it up by catalog #, find out if I already have it (once you get past a few hundred LPs, it's hard to remember them all), then ping allmusic.com or some other service for the rating and possibly a review.
As I have a good deal of experience with voice-activated IVR systems, I know its technically feasible. The biggest issue would be the lookup. It would need to be by the catalog #, since the grammar for artists and album names would be impossibly large (unless you have a system like 1-800-GOOG-411). The problem with lookup by catalog # is that services like Amazon.com aren't going to have them - they'll just have the CD catalog #. Also Amazon's ratings are not nearly so good as allmusic.com's - even the most mediocre albums get five stars, because they are non-professional ratings. Unfortunately, allmusic.com doesn't expose an API, while Amazon does - a nice, easy to use REST API.
So, will continue to search for an accessible online service that lists LPs along with CDs, with professional ratings and reviews...