Plaxo, the online address-book updater is up for sale, according to a Thursday report.

The Mountain View, California-based company is seeking as much as $100 million and has hired Revolution Partners to advise it on a deal, the New York Times reported.

The company founded in 2001 by Todd Masonis, Cameron Ring and Sean “Napster” Parker says it has 15 million registered users, although it has never turned a profit.

Sequoia Capital, Globespan Capital Partners, Harbinger Venture Management, and Cisco Systems as well as former Yahoo Chief Executive Timothy Koogle have backed the company with more than $20 million over the years.

In October, Plaxo lauched its Pulse service, which collects information from Twitter, MySpace, Digg, Facebook and many others. Its original goal was to keep address books up to date, but due to this intention, the company sent out millions of emails, which ended in the “spam” box. Moreover, the site faced additional difficulties as some providers stopped allowing Plaxo to use their services.

Rival Linkedln, a professional networking site, which is also backed by Sequoia, overshadows Plaxo may be a possible cause of its decline. Moreover, Linkedln has gathered momentum, as have full-featured social-networking sites such as MySpace and FaceBook.

Officials from Plaxo and Revolution Partners could not be reached for comment.