For actor Edward Norton, philanthropy and activism are practically in his genes so launching a website on Wednesday to encourage charity fundraising seemed natural to him.

Norton, 40, joined forces with a couple of Internet savvy friends to create Crowdrise (http://www.crowdrise.com) that gives people a free way to create their own fundraising pages to share through social networks, winning points and prizes along the way.

Crowdrise was developed after Norton found Twitter a huge help when he raised $1.2 million for his long-term cause, the Maasai Wilderness Conservation Trust, by running New York's marathon last year. Donors vied for prizes for sponsoring him.

People use Twitter or Facebook because it's a way to share their personal narrative but we wanted to give people a platform to say, these are the causes I care about, I am volunteering and sponsor me, Norton told Reuters in an interview.

We wanted it to be something with the substance of activism and engagement but the fun, ease and dynamism of social networking.

Norton, known for such movies as The Incredible Hulk, The Illusionist, and Fight Club, is a committed social and environmental activist, following in the footsteps of his grandfather and his father.

His grandfather, real estate developer James Rouse who designed the city of Columbia, Maryland, set up the non-profit Enterprise Foundation that aims to move families out of poverty and develop decent affordable housing in low-income areas.

His father, also called Edward, is a former federal prosecutor who is now a leading conservation advocate.

Norton himself is on the Enterprise Foundation's board of trustees as well as the boards of various other charities including the Maasai Wilderness Conservation Trust, which seeks to preserve the Maasai land and culture in Kenya, and the Friends of the High Line which is working to build a New York public park.

You do absorb what your parent are working on and I was always very tuned in to environmental advocacy issues, said Norton who is rarely seen in the gossip pages of celebrity pages and remains tight lipped about his personal life.

My grandfather was a very dynamic thinker in terms of how to motivate people and companies to get engaged in their communities, and he would love the grass-roots nature of this. He was a working class guy and believed in community based philanthropy rather than just having faith that big corporations will do the job.

A list of celebrities have already set up pages to promote their favorite causes on Crowdrise which is free to join and awards people points as they use the site. Top point earners are given the chance to win prizes.

The list includes actor Seth Rogen campaigning for Alzheimer's, Will Ferrell raising money for Cancer for College, and Russell Brand supporting the David Lynch Foundation.

Norton was adamant that he didn't twist any arms to get the growing number of celebrities on board.

People want to be able to use who they are to motivate their fans, said Norton who has been nominated for two Oscars for Primal Fear and American History X.

Technology has allowed for a kind of engagement between people with a public life and the people who are interested in them which is entirely new and potentially very powerful.

(Editing by Jill Serjeant)