For those who do research, either primary or secondary, it's a great way to collect references, organize them, and find them again. I do grounded theory research, which is very emergent, so I can tag themes in various online postings or articles and then later pull them up. This is also useful in organizing myself for class or a presentation I need to give somewhere. I can then tag a group of related items with the date or the name of the presentation (or class or topic). I'm just learning to use it. Do not know yet how to use the social networking aspects, which I think may be the most valuable. Any advice about that would be appreciated.