Very useful plugin. Would rate higher if the Firefox extension worked better.
Any time I hover over or highlight a browser element a memosnag icon pops up. It's annoying and I can't clear them all away. The only way to stop it is to disable the extension until I want to use it to save something.
The extension also stalls on Firefox Android a lot forcing me to bookmark the page so I can save with the desktop extension. It's frustrating because I like the app but the extension is buggy.