I have had a Pinterest account for a long time now, and I use it to collect fashions, recipes, shoes, all the things I love. I go back to it almost everyday to add to it or to look up something like an outfit, so I can buy the items or something similar while I'm out shopping. The recipes come in handy around the holidays as I am always looking for something new to add to the menu. I am new to Diigo but so I may be a little biased still. However, I have noticed on a professional level, you can highlight texts on saved sites for both Diigo and Pinterest, you can also use multiple tags and you can copy and paste from original articles to appear in comments about the site. Other viewers of my site can post comments whether Diigo or Pinterest and they can follow me and I can follow them. They can also enjoy all my postings or like them. f
On Pinterest you are offered a lot of posts related to the items you tend to favor which is always fun and interesting. Not so on Diigo, this site appears to be more professional in that you don't use it to post photos of foods to share, which is not to say you cannot save recipes or fashions, just not in the same way. Diigo is a site better suited to collecting and sharing information of a professional nature. I am not yet aware that this site offers suggestions of related article.
I would recommend both sites but for specific reasons. I view Pinterest as a fun place to collect, view and share your interests, but I like Diigo for my professional life where I can readily go to look up articles I saved that might help me with my profession.
https://www.pinterest.com/michellegaskin/
The Literary Maven/Bullying is one of the listed on my Pinterest under Language teaching, these are the educational reasons you can use these sites for. You can find anything on Pinterest to help you in the classroom just like you can to help you in fashion, for instance grammar techniques.