Econsultancy spoke to 1,100 client-side marketers, PR professionals and digital agencies to establish how they were using online and social media.
Nearly half of respondents - 46 per cent - said they did not use reputation or 'buzz' monitoring tools to discover what was being said about their brand on the web.
'This is clearly not acceptable, but I'm not surprised,' said NixonMcInnes director Will McInnes. 'In about nine months' time, this will be a sackable offence, if the comms head hasn't implemented it. People are flying blind.'
In recent months, brands such as oil firm Trafigura and telecoms company Spinvox have seen their reputations hit by crises fuelled by social networking sites.
Andrew West, managing director corporate, Hotwire, said: 'Nobody can afford to ignore buzz monitoring. We use some of the available tools and have our own technology.'
Of those surveyed, only 17 per cent were using technology to analyse sentiment.
West said several sentiment-monitoring products were 'expensive'. But he added: 'Intelligent interpretation of sentiment provides us with important data.'
The survey was carried out in association with BigMouthMedia.