SalesCrunch (disclosure a client) is an online meeting platform that gives your real, hard statistics about how effective your meetings are: how many people pay attention, what % of your presentation is read, etc.
They analyzed the aggregate statistics of their entire client base and boiled the data down in an infographic. The key points will not surprise regular readers here: shorter meetings are better, shorter decks are better, and listening is better than doing all the talking. But for the first time, everything is backed up by hard data. Download the high-res version of the infographic here.