Does anyone know exactly how many people you can add to a conference call?
AFAIK, there is no hard and fast limit. The exact number of people that you can join into the call depends on the model of the phone. Most businesses that hold conference calls regularly use some sort of hosting service, which avoids limitations imposed by the handsets. I personally have never really found it practical to have more than three people on the line at one time in any case though, so I've never really done any dedicated research on the subject.