When you are ready to stand up to speak
Perhaps you should consider sitting down.
When you are asked to give a short talk at the big company gathering, or contribute a few minutes in a large group discussion, and you're ready to stand up and have all eyes on you, sometimes, perhaps, it makes sense to sit down instead.
If you're a bit nervous and you've written everything out and your main goal is to say nothing controversial, nothing memorable, nothing that might get you in trouble... well, why say it?
If your job is to act as filler, to say a small not-so-funny joke and then stall for a minute or two, or your job is to put in an appearance, or perhaps to make sure that senior management knows you exist, I bet there are far better ways to pull that off.
The traffic engineers in New York think nothing of wasting two minutes of each person's time as they approach a gated toll booth. Multiply that two minutes times 12,000 people and it's a lot of hours every day, isn't it? If you're speaking to a thousand people for just a minute or two or three and you don't have anything in particular to communicate, you've just wasted many hours of the most expensive time your organization has purchased this year.
Big groups are perfect places for the efficient communication of emotion. They are terrific for the impact that comes from watching your peers shake their heads in agreement simultaneously. The power of groupthink doesn't happen in an electronic memo, but it can sure be powerful in a big room.
The flipside is obvious: if all you want to do is recite a fact or a policy or worst of all, not really be noticed, then it's probably better to just sit down.