The report by Spectrum Consulting said voluntary sector organisations found social media less influential than PR agencies and commercial and public sector organisations did.
Only 18 per cent of not-for-profit organisations said the potential impact of blogs and online news was underestimated - a clear 20 per cent lower than in any other sector. Only 35 per cent agreed that it was very important to understand the content of online media.
'Given the effectiveness of blogs and online news for reaching target audiences and the low cost of using and monitoring them, we believe the not-for-profit sector risks missing a major trick by failing to recognise the benefits of social media,' said the report.
The Alzheimer's Society CEO Neil Hunt agreed that the voluntary sector should not underestimate the importance of online media.
'If some charities have been slow to use this medium, then I expect to see more and more uptake as the full potential of online media is recognised,' he said.
'The Alzheimer's Society has put increasing emphasis on working with online media. It is a quick and cost effective medium for charities who balance tight budgets with the important role of raising awareness and funds.'