Currently owned by its original creator at
Curious Labs, Poser is a program used to manipulate and animate preexisting models (usually human figures, but it can handle animals reasonably well) to create static images or animation. It has no internal capacity for
modeling.
The most popular use for Poser on the net appears to be the creation of extremely low-quality pornography. A "Pro Pack" add-on was recently released, which allows the program to export animation in a variety of formats, including Flash, Lightwave, and 3D Studio.
The Flash export is essentially standalone, in that it creates a full Flash animation from the Poser file. The other two are plug-ins which allow Poser files to be opened within the high-end graphics packages for decent rendering.