Professional Network Viadeo Buying Contact Manager Unyk

French LinkedIn clone Viadeo is buying Canadian online address book manager Unyk in a move apparently designed to enhance its own contact management.

Terms including price are being kept under wraps (Update: It’s both cash and a share swap). Unyk’s 16 million members will become Viadeo members, giving the latter over 25 million users.

Unyk looks very much like Plaxo. It lets users sync up address books from local machines and web services, then, if contacts are also Unyk users, will update your address book with any changes they make. Unyk claims 600,000 new members a month.

Like Germany’s Xing, Viadeo has been on the acquisition trail in a bid to rival both LinkedIn and Xing itself. After raising