Exceptions needed Rated 4 out of 5 stars
Nice and very useful add-on. However, it doesn't play very nicely with Google Spreadsheet (and maybe other similar web services): simply clicking on a cell will trigger the auto-copy mechanism. Most of the time I click on an empty cell precisely because I want to paste something in it, and because of auto-copy, the clipboard is emptied before I can paste what I want. Very annoying.
Fortunately I use a multi-clipboard software (namely: Ditto, for Windows) so I'm usually able to retrieve the previously copied element, but it's annoying nonetheless.
My suggestion would be to implement a simple blacklist function so that people would be able to specify some websites on which AutoCopy would be automatically disabled. (Or an option to disable this specific behavior in Google Spreadsheet.)