I've established profiles on a number of websites, both for business and for fun. If you are on these networks, please shoot me an invite:
* Del.icio.us - a social bookmarking site, where users tag websites to be saved and shared. It's more flexible than Internet Explorer Favorites or Firefox bookmarks because it's not hierarchical. You can give a website multiple tags. E.g. You could save this blog, tagged with "blog," "technology," and "business." Then, once sites are saved in del.icio.us you can syndicated them in all sorts of cool ways (link rolls, tag clouds, etc.).
* Digg - a social news site where users determine the content. Probably the most popular of its kind (others of note include Slashdot, Rojo, Reddit, Netscape, and Newsvine), users post news stories and others digg, or vote on, their favorites. Popular stories with the most diggs are pushed to the front page.
* LinkedIn - a business networking site (among others like Ryze and Spoke), it allows members to keep up with each other's skills, jobs, projects, and entrepreneurial pursuits. It's also a great source of leads for business partners and potential hires. I also use it just to keep in touch with my friends and associates.

