Social toolbox

I am extensively online for both my personal & professional lives. Over the years, I've come to integrate a number of tools for keeping organized whilst socializing. My main requirements are:

• Capacity to organize feed items (e.g. categorize)
• Capacity to publish (share) selected feed items
• Capacity to subscribe to feeds
• Capacity to view feed items in real-time (as much as possible)
• Capacity to view feed items in one window

Following is a diagram of my current toolbox that meets these requirements:

Sites without an RSS/ATOM feed

Once in a while I encounter sites without an RSS/ATOM feed (mainly on "local sites" e.g. town news) . I use Yahoo! Pipes to build a feed in such cases.

What is Diigo?

Diigo is a cool service: it is a social bookmarking site sporting the added features of "text highlighting" and sticky notes.

What tools would you suggest I add to my arsenal?