Am I the only one who has never heard of Diigo.com?  I feel like a dinosaur.  I wish had learned about this Internet tool sooner.  

Diigo.com has four functions: highlighting text on the Internet, bookmarking sites with important text, annotating text with Sticky Note, and Sharing sites and annotated text with collaborators.

The Highlight function simply lets you mark selected text with color to indicate importance. You can select different highlight colors from the drop-down box to indicate different categories.

The Bookmark function lets you save the URL of the page and add notes, tags and descriptions with it. When you view the bookmark on Diigo, all the annotations (highlighted text and sticky notes) will appear below it.  This function will not save the whole article into Diigo, but only the URL.  You also have the option to cache a page. 

To cache a page is a way of taking a picture of it at that moment.  If the owner of the page changes or deletes the page you will still have the cached page exactly that way it appeared when you saved it in the Diigo database.  This is a really useful feature to teach students just learning to do research.  For graduate students, it is suggested that they upgrade to the Premium Plan for unlimited cache and highlights.

Diigo is free for unlimited bookmarks but is limited to 1000 highlights per year and 30 cached pages. A paid service of Basic ($20/yr) and Premium ($40/yr) is available for more unlimited and ad-free options.

Diigo gives you the option to keep your bookmarks and annotations private, and allows you to create a folder for bookmarks that you would like to read later.

The Sticky Note function will let you post a note anywhere in the article as a graphic reminder. You can add more information to an existing note.

The Share function lets you share the annotated link of the article to other collaborators.

Diigo is a tool for organizing and saving research material. Once you’re done with all the highlighting bookmarking and annotating, you can log into your Diigo account to view all saved information.  The pages are organized according to the categories and tags that you stipulated when you first saved it.