Diigo

I did have a Delicious account up until I was introduced to Diigo. I was very excited about using the Diigolet to bookmark, highlight, post a sticky note, tag, and share with a group. Yes Delicious and Diigo are great for bookmarking but I am excited to explore more of what Diigo has to offer. At this point in time I would say that I understand the basics of bookmarking, taging, sharing with a group but I need to spend more time with connecting with other professionals. I have joined two other groups to see if I am going to be able to apply what they have to offer. I am looking for a resource guide to help narrow my search. Any suggestions??