Yomego assigned the Conservative and Labour leaders a score out of 100 for their online reputation. The index incorporate measures for the volume and newness of social media 'noise' or references and whether they are positive or negative.
and Brown actually scored virtually the same - around 70 out of 100 - for the volume of noise about them and the newness of it, over the three-month timeframe of the audit.
However, Brown scored just 18 for tone of sentiment against Cameron's 60, and just 13 for "recency of sentiment" against 51 for the leader of the Tories. The latter measure is there to highlight the most recently expressed sentiment, which can give evidence of changing trends in popularity.
Despite Cameron expressing his worry in July that "too many twits might make a twat", it is Labour that seems to be inspiring lots of noise and brickbats from the UK's 30 million social network users.
A spokesman for Yomego said: "In Mr Brown's case there was lots of noise but opinion was almost universally unenthusiastic with his 'sentiment' score lower than that achieved by British National Party leader Nick Griffin."
Liberal Democrat leader Nick Clegg solidly occupies the middle ground with an overall score of 54, while US president Barack Obama gets 78.
Although Yomego released its findings to coincide with the Labour Party conference this week, there is no political party among its client list, which includes Ladbrokes, Irish food company Tayto and GMTV.
It will be releasing scores for consumer brands and for television programmes at Mipcom, the annual get-together for programme makers and broadcasters, in early October.
The reason it chose a numerical score to sum up its audits is that it provides an attractive metric at board level and gives companies a good idea of their performance relative to rivals, according to Yomego's insight manager Joe Hughes.
The system that produces the numbers combines a technology-based operation with a human team. The former is capable of sentiment scoring by using natural language filters but, admits Hughes, can be misled by sarcasm.
The human team double checks the computer's sentiment scoring and examines the potential audience of a blogger or group to identify their influence.
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