The other person or group actually knows from experience what you are going through, and you can mutually share tips for getting through certain treatments, ways of coping with family concerns and emotions that you have about your diagnosis. You may discover new community resources that are recommended from first hand experience. Someone who has gone through applications for entitlements, organizing hospital bills, or appealing insurance denials can stop you from making mistakes they might have made, or provide useful hints. More and more people are researching their own cancers, and are usually willing to share information they have found, or sources of reputable informational material. Some people report finding wonderful, meaningful friendships through connecting with others who have their same diagnosis.
People often report that providing support to someone else is a rewarding experience.
It can be difficult to match you with someone that you will be compatible with. Sometimes a one on one match may not work simply because of personality differences. This is less of a risk when you join a listserv or support group. The person you are matched with or people in the group may be at different stages of their cancer than you are. It may be hard to hear their stories about advanced cancer, or stories about how well they are doing, if you are having a tougher time.