The charity's online community is more than five years old, and is there for anyone who has cancer, has had cancer or knows someone with cancer.
The online community had 92,729 unique users in 2010. It has more than 57,000 registered users, growing in number by about 1,000 each month and posting on the forum every 13 minutes on average, which is 3,368 a month.
It offers a wealth of resources, forums, social media and support groups, covering practical and emotional issues, coping with loss, treatment and surgery, living beyond cancer, friends and family, and more.
What those members say about their internet support:
"I’m only strong and positive because I can go online and be as honest as I like about how scared I am. I’ll have people there who can get me through it, then I can get back to the rest of my life."
"I think if it wasn’t for the internet I’d have probably fallen apart because you feel like you have to turn somewhere and the internet is the safest place to do it."
Katie Smith, head of digital media at Macmillan Cancer Support, said: "There are people out there who need help, and people that are willing to give it. And I think that’s what makes the internet so great because there are no boundaries. There are no ‘open hours’ if you like. There’s always somebody there.
"Our online community is as active, cohesive and dynamic as any offline community you could find. Every hour, people discover that others have gone through the same experiences and are there for them. They find a voice to express feelings they’ve kept inside."