Simplybusiness.co.uk is Man Bites Dog's first strictly online client, with MD Claire Mason saying the agency was 'actively growing its technology portfolio'.
The Brighton-based B2B consultancy, which won New Consultancy of the Year at the 2007 PRWeek Awards, has traditionally specialised in business comms for the professional services industry.
Last week Mason and her tech team travelled to San Francisco to meet global technology companies.
Simplybusiness.co.uk enables 80,000 small businesses a month to compare insurance and finance quotes.
Man Bites Dog is the firm's first agency and will work to specifically promote its insurance offering.
The PR campaign will target British entrepreneurs and small- to medium-size enterprises across a variety of sectors. The agency will aim to get website exposure in national newspapers and trade publications, with a particular focus on online media.
Mason said the website was in an ideal position to help businesses during a crisis. 'Companies are looking to cut costs - turning to comparators to ensure best value from their insurance,' she said.