Functionality
For this review we’re testing SpareChange’s WordPress plugin. Before installing, you’ll need a SpareChange account. After creating an account and installing the plugin from wordpress.org, head over to Sidebar > SpareChange Options. Enter the API key(you can get this from SpareChange’s dashboard) and you’re good to go.

There’s a lot of functionality missing from the plugin. There should be options to show opt-in before the mining starts, some sort of throttling on mobile devices(because they are very underpowered and hashing XMR could slow down the browser), notification to show that mining has started, etc.
As for now I recommend including sparechange.js directly from their main website and embedding it instead of downloading this plugin.