Venturebeat (opens in new tab) has resurrected the rumour about a possible acquisition of Plaxo by Facebook.
The business social network would be a perfect complement to churlish, ill mannered Facebook and would provide it with an instant entry in the world of serious social networking.
One of Plaxo's forthcoming tools, Pulse, was at the centre of a row between Celebrity Blogger Robert Scoble and Facebook as the former tried to use Pulse to transfer his friends' data.
As of December 2007 (opens in new tab), Plaxo had around 35 million users including 15 million address book accounts hosted through partnerships (according to Techcrunch), a substantial chunk of which might not be on Facebook - so no real overlap here.
The New York Times, via Red Herring (opens in new tab), understands that Plaxo was asking for around USD 100 million which would value each user at roughly USD 3, an absolute bargain compared to the price for Facebook users.
Linkedin could also be interested in Plaxo and its Pulse tool - which allows you to sync contacts on Outlook and AIM, something Linkedin is lacking at present.
Ultimately though, it is just a matter of time before Facebook make a move in the more lucrative and less competitive business social network arena, with or without acquisitions.