Jaiku is the new startup I co-founded with Petteri Koponen, Mika Raento and Teemu Kurppa. It’s a social phonebook that displays the real-time availability and location of your contacts. We call this rich presence.

With the Jaiku mobile application, you can share your location (neighborhood, city, country) based on cell tower positioning; your availability (based on whether your phone’s ringer is on or off); an IM-style presence line; current and upcoming calendar events; people and devices nearby (based on Bluetooth scanning); and how long your phone has been idle.

You can share this information with your contacts’ mobile phones. You can also create a badge for your blog, MySpace profile or any other Web page that shows your real-time presence on the Web.

Here’s my real-time presence badge:

The beta version of the mobile application is for Nokia S60 Second Edition phones only (see the list of compatible models). We’re planning to make versions for other models in the future, and enable anybody to update their rich presence on the Web or from any mobile by sending in simple text messages.

Jaiku doesn’t include rich presence from Web feeds yet – but I think it will be cool to show the latest blog post / photo / bookmark, or the music track you last listened to.

Give it a spin and post your comments on the Jaikido blog!