I have found the highlighting and comment tools so useful, that I have now uploaded a gutenburg book onto my blog, so that I could highlight it and comment while I read, then have the collection of snips and notes at the end. Why can't diigo store things separately for files on a hard drive, granted that they are still being viewed in the browser?
second feature: It wasn't until after I'd been using diigo for a while that I noticed the option to have bookmarks put onto my bookmarks toolbar or menu. This option should have a "make universal" option. I will not be visiting each page I've tagged and putting them into my bookmarks menu individually.
To explain, on the second page of the options menu for the diigo toolbar (on Mac), at the bottom, one has the option to add bookmarks to the "local 'bookmarks' folder of your browser". Now that I've made this selection, I have some, not all, bookmarks in there, with tags all pell-mell.
The Diigo people cannot possibly be unaware of this....