Hi Walter,
I’ll answer your questions, one by one, and at the end I’ll let you two links to the online demo of plugin.
Q: How it interfaces with Facebook. And can you embed a player directly into a Facebook post?
A: Not really, the Music Store inserts only the “Like” button in the songs pages, and does not includes the player directly in a Facebook post.
Q: Different players/widgets that can be placed on websites.
A: The Music Store uses MediaElement.js as audio player, that includes three different skins for its player. About widgets, the premium version of Music Store implements two widgets to insert a product, or products list on sidebars.
Q: We saw music store on an artist’s website where all items were in one continuous column, requiring scrolling. Can they be displayed with more than one column, and can we see examples of that?
A: Through the shortcode it is possible define the number of columns for the store’s page [music_store columns=”3″]. The option is available from the insertion dialog too:
http://ps.w.org/music-store/assets/screenshot-07.jpg?rev=809272
Q: does the plugin interface smoothly with mobile devices?
A: Yes, the plugin was made following the principles of responsive design, and its player is supported by the most popular mobile devices.
The links to the online demo:
http://www.dreamweaverdownloads.com/demos/music-store/
http://www.dreamweaverdownloads.com/demos/music-store/wp-login.php
Best regards.