The criticism came during a seminar held to mark the publication of Contentious Citizens: Civil Society's Role in Campaigning for Social Change by the Young Foundation and the Carnegie UK Trust.
Liz Atkins, director of public policy at the NCVO and former head of policy at the NSPCC, questioned the assumption that the charity's Full Stop campaign to end violence against children was a great success.
She said: "It might have been successful in raising a lot of money, but it hasn't managed to achieve any other aims, such as having a real impact on child abuse."
Geoff Mulgan, director of the Young Foundation, accused the Make Poverty History coalition of "throwing away thousands of supporters" at the end of its campaign and not channelling their support behind a new cause.
Matthew Sowemimo, campaigns and communications manager at the Sheila McKechnie Foundation, warned campaigning organisations not to rely too heavily on the internet.
He said: "A significant proportion of the population does not have access to broadband. There's a danger that, by only using the web to communicate, you will simply re-enfranchise the middle class, who already have a voice."
Sowemimo urged greater use of text messaging, on the grounds that most people have mobile phones.