I can show you metadata transfer working between PlayIt Live and Rocket Broadcaster.
They are both on the same PC in this case but it also works using a mapped share between two different PCs.
The metadata is a PRO (paid) feature on Rocket but does work.
There are some caveats. Opus metadata doesn't work (a Rocket/Opus limitation I believe) and I have seen PlayIt Live produce blank "nowplaying.txt" files.
I think this was related to dragging items into the playlist but I haven't investigated it.
From my experience the Rocket streaming of the information in the text file is solid.
After a bit of experimentation I can replicate the blank "nowplaying.txt" file.
It happens if you play the same file twice in succession.
It's nothing to do with Rocket Broadcaster, the file as viewed on a different PC (with share access to where the file lives) has a length of 0kB.
v2.06.2.2785 if it helps.
how do we embed now playing onto our site
I can see two approaches.
1) Use the "now playing" plug in to save a text file on the computer (or a mapped share) and get some software (I don't know what) to "push" it to the website.
2) Get whoever wrote the website to accept one of the HTTP or TCP/IP requests that the "now playing" plug in can generate.
This is more elegant.
I have made this work with a Barix Instreamer but it wasn't easy.
I don't know quite how the website would accept this information but the plugin is designed to feed TuneIn or similar so I'm fairly sure it could (in theory at least) work.
Some of the streaming services have widgets which show metadata, you could look at using one of those services.