Silent Meetings

Have you ever heard of silent meetings? May be not, I just made this name up. But many times it happens that only one person is speaking and presenting in a meeting and not even single person is asking any questions or giving and comments. Why does this happen? I was discussing this with my manager after when he got done with one of such 'Silent Meeting'. He was like I guess silence is good, meaning not many people objected about anything we said and nobody had any question as well. So may be we are on top of everything. Or on the other hand, the people listening have no clue what we are talking about and they have too many even basic questions about the meeting that they fear presenting it to the speaker making him or her uncomfortable. So I say people, be interactive if you really want to get something out of a meeting or a conversation. Else there will be no use of such meetings