I think it can be very useful for everyone, once a diagnosis has been made - access to help and support groups, further details of the condition etc, but without expertise and training, trying to use the internet as a self-diagnostic tool is fraught with difficulties, not least mis-diagnosis, or assuming the worst case scenario, or falling for quackery.
In general I am in favour of people having as much information as possible, because in theory an informed patient is one better able to manage their condition; but people should be wary of what site on the internet they place a value....