Web: Evernote is a brilliant app if you use it right, but the more you put into your notebooks, the more overwhelming it can get. We've talked about the benefits of mind-mapping, so if you like that, Mohiomap takes all your Evernote data and turns it into a visual map for easy navigation.
Once you grant Mohiomap access to your Evernote, it works like most other mind-mapping tools, starting with your account and branching out into nodes and sub-nodes for notebooks, tags and notes. You can choose to view the notes and links in Mohiomap itself or open them in a new window, the Evernote app or the Evernote webapp. You can also pin any node on the map.
A cool mechanism is the ability to view the map by relevance to any chosen point you click on, which lets you adjust how much information you will see. But the best part is the ability to drag-and-drop your tags from one node to another, forming new links visually -- you have to try it out to see how useful it can be in making connections within your notes.