A new infographic from Gerson Lehrman Group's GPlus.com maps out the current online music on-demand landscape from the top 10 players. You can see at a glance what the monthly fees are, whether or not you can add your own tunes to their online libraries, how many current users, whether they have mobile, Web or desktop apps and what the major features are. If you were thinking about trying one of these services, this is a handy place to start to evaluate their basics.
Certainly, the idea that we need to carry our entire music collection on our own hard drives is becoming less important as these on-demand services improve and become more popular and feature-complete. How both Facebook and Apple's iTunes will handle these competitors remains to be seen.