Initial reports are MAC and PC using TIDAL as a media source.
What made Sooloos and Meridian Digital Music System great was that it used All Music Guide's Database of song metadata.
AllMusic | Music Search, Recommendations, Videos and Reviews
My hunch is that once again Roon Labs will use AMG's services.
The "So What?" is... if you poke around on AMG's website you will find an album that you know and like.
Click on it.
From there you can get a brief bio or background of the album and all this data that is linked to the album. For example you can select the mastering engineer and change your view to see all the music that the mastering engineer had a hand in making. Or there was a killer saxophone solo in the recording you just heard-- pull up that recording in AMG, select that Saxophonist and see all the other contributions that musician made to music. Perhaps see all the other collaborations and so on.
Music is linked in so many ways and the object of Roon/Meridian stuff is to make the linking convenient and easy. Just think of the AMG website as the interface, but when you select a track it plays in TIDAL. I think that is what it is in a nutshell. Lets not forget that Meridian Quality Authenticated or MQA is going to tie in at a later date. What that means is that you may have albums that have been authenticated to be of the best fidelity or the best "version of that version*"
J River Media Center already does a similar concept, however when you use the JRMC browser to view the data on AMG's site you may not have the track that is referenced AND the AMG site won't play the song that you have in your own library.
However, JRMC has smart playlists that you can simply filter by the meta data and achieve similar functions. i.e. Artist on album or Jazz from 1978-83 with 80 Beats per minute and lower.
Roon Audio should be a great discovery tool. Still you can do much of it's capability on your own. It won't have the integration and the multi format support (DXD, DSD, High BITRATE PCM), but it should be fun.
*It's a complicated process to get the right recordings that the population wants- many have been destroyed or there requires a good deal of money to license a re release