[drac]

even when everyone dials in, the people using a cellphone or joining conference calls while travelling are at a distinct disadvantage. Any number of calls I join have at least one guy having to drop out and come back in because the signal keeps fading.

The other thing I've noticed with a large number of dial-in participants is that there can be a lot of silent attendees and very few people talking. YMMV

[count]

Large numbers of silent attendees is normal in meetings with lots of people in person too - most people just don't have anything to say!