Many charities have little or no funds available for web design and development. As a developer I like to choose a charity each year for which I will undertake some development work for. It may be designing them a basic website, designing a logo or even promoting them of the social media sites.
Marketing is vital to many charities tying to obtain funding and online marketing plays a big part in that. Web development can be complex, but to create a simple basic static site can take as little as a few hours. This then gives many charities a platform to start marketing from and with the help of social media sites such as Facebook and Twitter, can easily spread the word about what work they are doing and for what cause.
If you are a web developer, I would ask that you consider if this is something you could do to help a local charity out. You may also get some publicity out of it which of course is a bonus but the feel good factor outweighs this.