Dot-com banker Quattrone joins Google as an adviser

Quattrone will look at mergers and acquisitions and ways to combat the potential threat of a combined Microsoft and Yahoo.

It is the first role for the merchant banker since being cleared by a judge last year of obstruction of justice charges.

Google chief executive Eric Schmidt and Quattrone are old friends and colleagues and the San Francisco-based banker was one of the first to see the potential of Google when it was still in its infancy in the late 1990s. Quattrone's star fell with a prosecution, begun in 2003, tied to the destruction of emails during a probe of dot-com era initial public offerings when in charge of Credit Suisse's Silicon Valley operations.

Federal prosecutors accused him of forwarding an email to colleagues in December 2000 suggesting that it was "time to clean up those files".

He spent years fighting to clear his name in court. His first trial on obstruction charges ended in a hung jury. He was convicted in a second trial but an appeals court overturned the conviction. Quattrone and former colleagues have now started Qatalyst Group, a tech-focused investment banking boutique based in San Francisco, to provide merger and corporate finance advice to technology companies.

"I look forward to working with him again and am very enthusiastic about Qatalyst's prospects for success," Google chief Eric Schmidt said.

But Quattrone and Google face major obstacles to joining the current web company mergers and acquisitions boom, given the firm's dominant position in the search and online advertising field.