Generally, you cannot export the obj file for someone else's use. It is due in part to copyright, and in part to the software licenses for Poser 4 and for the DAZ models, though the DAZ license is more explicit about this than the P4 license (at least when I bought it). Giving away a picture of a posed poser figure does not violate the license; in fact the DAZ license (which is, btw, on DAZ3D's FAQ page) expressly permits said use. Although there could arguably be a copyright question, the licenses permit this use (and thereby eliminate the copyright issue) because there would not be much of a market for a graphics program if you can't distribute the graphics. One caviat: there was a small controversy here over changes to the DAZ licenses for Michael 2 and Stephanie, which Dan Farr said was intended to bar collections of multiple renders so comprehensive that the purchaser of said collection would not need to buy the model, but which arguably was written more broadly.