I've been away from the DVS/Digital DJing solutions for a while and slowly coming back in, moving in from another product. One thing that I find incredibly useful in my huge library is the ability to have a column for ID3 Tag Ranking/Rating. 6 years back another product I was using was working fine, and I was able to see the information via other programs as well (Mediamonkey (win), Winamp etc, and even in a file browser.). Here's the specification for ID3 Ranking.Rating sniped from Wikipedia. Having this feature would allow for easier sorting, and even offer a whole new set of Smart Crate Ideas.

"However, there is a "Popularimeter" frame in the ID3v2 specification meant for this purpose. The frame is called POPM and Windows Explorer, Windows Media Player, Winamp, foobar2000, media monkey, and other software all map roughly the same ranges of 0–255 to a 0–5 stars value for display.

The following list details how Windows Explorer reads and writes the POPM frame:

224-255 = 5 stars when READ with Windows Explorer, writes 255
160-223 = 4 stars when READ with Windows Explorer, writes 196
096-159 = 3 stars when READ with Windows Explorer, writes 128
032-095 = 2 stars when READ with Windows Explorer, writes 64
001-031 = 1 star when READ with Windows Explorer, writes 1

Windows Explorer uses the following syntax:

Windows Media Player 9 Series | 255 | 0

The 0 is the play counter portion of POPM as per the ID3v2 POPM specification, which is not to be confused or conflated with the PCNT frame, which is a separate frame meant entirely for playcounts. If an app supports granularity however, it should write 1 for one full star, and then 2–31 would be granular points under one full star. Notably, the ID string Windows uses is not an email address, as called for in the specifications. Further, Windows Explorer and Windows Media Player up to and including Windows 7 and Windows Media Player 12 (possibly beyond)[ contain a bug such that, if one were to use them to rate files, any Replay Gain tags one would have will be corrupted. WMP also writes the same values as described above, and reads the same way as well, EXCEPT for the cutoff between 4 and 5 stars, which is slightly different and basically of no consequence. WMP uses 221/222 instead, for reasons that are not clear."