Desired:
A gadget where members who are currently logged into your site are displayed.

There would be a list of those who are logged in, with links to their profile pages. Members would have the ability to indicate if they want to be included in this gadget, and for those that do their field-level privacy settings would be respected.

This could be used to show visitors to the site, or logged in members (by putting it in a member restricted area), who is currently on the site which can help encourage communication between people (by using the Member contact form, mailing them directly, or forums and blog comments).