The London-based company aims to grow rapidly through word-of-mouth reputation, with an emphasis on quality, client service and value for money.
Opinium is 25% owned by PR consultancy Lansons Communications and 75% owned by private individuals.
Tony Langham, chief executive at Lansons, has taken the role of non-executive chairman.
Opinium will use panel research technology from Vision Critical to help clients obtain sharper insights into their target markets.
The agency said that it plans to capitalise on the demand for quality-driven online research. It points to a recent independent study predicting that online market research will reach US levels of penetration within the next two years.
A separate study points to growth of 80% in the use of online market research within Europe, while overall UK market research turnover continues to grow.
Hodson said: "We have already been pleased by the appetite from clients for quality-driven online research. We will soon be known as a lean, keen, technology-enabled agency, combining high standards and low costs."
Opinium will initially offer clients access to weekly low-cost online omnibus surveys and over time it will provide access to a number of specialist panels.