Investors still believe there is money to made from social networking websites. LinkedIn today won an additional $53 million (£27.1 million)in funding to back a major expansion in the UK, giving the US-based site a valuation of around $1 billion.

LinkedIn, which has around 23 million users, is aimed at business people and professionals rather than students and teenagers who have tended to prefer bigger sites such as Facebook and MySpace.

LinkedIn is using the new injection of capital to expand its European operations, starting in the UK, where it already has a presence. The site claims executives from every company on the FTSE 100 are members.

Bain Capital Venture is lead investor in the latest round of funding, although several other existing investors including Sequoia Capital, Grey Lock Partners and Bessemer Venture Partners also stumped up cash.

Jeffrey Glass, partner at Bain Capital Ventures, said: "Unlike other networks, user engagement on LinkedIn actually increases over time."