this looks like a great little plugin!
I am looking to sell protected content with another plugin called Pay Per Post, which links in with Woocommerce.
The customer pays for access via a 'product' in Woocommerce, which gives them access to a restricted wordpress 'page'. I want to stop people sharing their login once content is bought.
I think your plugin will do this as the content is just standard Wordpress, but thought I'd better ask...
Yes, I think this plugin would work for you. But I have to note, that it will stop people signing in from two machines **at the same time**, but it does not keep a history of machines. For example if user logged in from one computer, logged out and then (he himself, or a different person) logged in from a different machine, this would be allowed.
Also, I do offer 14 day money-back guarantee, if you find it unsuitable for you.