Socialize or Business...The Uses of Cool Tools

How many new cool tools are out there do you suppose? Many, I'm sure. Which are the easiest to use? Social tools such as Facebook and MySpace are here, yet Tagged is here too. How many "identities" must one create? This blog entry, I hope, will entail information about cool tools used by users and which may be up and coming. Web 2.0 tools are being used in higher education and some K-12. Are they in your schools? (UH, I know, but in other schools you are affiliated with). Please list tools used by yourself, your students, your collegues, or your work and how they are used; social, business, either, or neither. Thank you for your input. Maybe there will be some tools listed you've never heard of that may be YOUR next experience.