YouTube will add a new analytics service called Hot Spots this week or next, aimed at helping video creators drill down to see which parts of their clips are most popular — or not. As we understand it, the service would alert you to developments such as when people drop off (in other words, your video is too long) and when people watch a certain portion over and over again (in other words, you should have put that in slow-mo).

The feature was first mentioned in an AdAge story about YouTube’s Insight product, which provides demographic and other information to YouTube publishers.

A YouTube spokesperson confirmed the upcoming release of Hot Spots (which he said is two words, not one, as printed in AdAge) and said the final details were being nailed down.

Video analytics and hosting companies such as Visible Measures and Ooyala also offer such tools. TubeMogul, though it doesn’t host video, is also working on ways to get in-player viewer engagement metrics from embeds and video sites themselves.