Explain Poses?

Poses are... poses or animations that are downloaded and not part of the actual game, and as such they require other mods to use. They can really add a lot if you're a Simlit writer or storyteller, as they allow your Sims to pose in ways that they otherwise would be unable to. Unless you take a lot of screenshots or write stories about your sim, they won't be much use to you as I *THINK* they just make your sim stand in that pose until you cancel the posing action.

I write (when inspiration strikes in a useful way), and I'm REALLY interested in learning how to use the pose player, teleporter, etc. (mods that are required for using poses) to improve my screenshots.