OCD thrives on the cyclical nature of obsession and compulsion. Since obsessions cannot be prevented, the only way to cure the disease is to open the cycle by preventing the acting out of the compulsion. Every obsession has its own compulsion, but there is one compulsion which is common to all obsessions and that is reassurance.
Patients join forums to get reassured from fellow sufferers. This is okay for other forums but not OCD forums. Seeking reassurance is like acting out a compulsion and is likely to delay recovery. Likewise by giving reassurance to a fellow patient you are not helping him but helping delay his recovery process by closing his loop.