There are other sites that serve a similar purpose, but Count Me In, which gets 8,000 visitors a month, is the only one that is free to both the media and the 500 charities that use it.
About 1,000 different events are posted on it every month and it can be seen on the Community Channel, with which it has links. It is also used by schoolteachers planning lessons for the citizenship module of the national curriculum.
Gareth Jenkins, the editor of the site, is looking at expanding it to offer calendars based on specific themes, such as peace. He has applied to the Joseph Rowntree Foundation for the necessary funding.
The microsite would include events such as lectures and marches. Jenkins is looking at the possibility of environmental and international calendars as well.
"The funding from Whitbread was only ever meant to last for two years, so we always knew we would eventually have to find new sponsors," Jenkins says. "We get a lot of positive feedback and feel it is important to keep the resource going."
But given the continuing debate about whether awareness days are still effective, some might wonder whether the sector needs the Count Me In Calendar at all.
Caroline Diehl, chief executive of the Media Trust, believes the significance of the debate has been exaggerated.
"For almost as long as I can remember, people have argued that there are too many awareness days and months," she says. "But if they are done cleverly by charities and promoted properly, they can still work.
"Journalists can be lazy and they like to be given things on a plate.
The fact that there are so many awareness days now means they can pick and choose what works best for them. Count Me In is a fantastic resource."
But not everyone believes the site is useful. A spokeswoman for Lupus UK, which posted its awareness month on the site recently, says: "I can't say it has been very effective for us.
"We haven't had a single call about it as a result of being on the site."