That's probably it, but if you really want to minimize the size of your exports, metadata will have only a tiny impact on the size of your export. The options under Image Sizing, and also the quality slider, will have a much bigger impact.
dj_paige, I'm exporting for use on a blog. Right now I'm at 800 pix at the wides, at 72dpi and 85% quality. Would that be a relatively small file size? I'm still figuring this all out and appreciate your guidance.
That should be small, but if your going to put the photo on a blog, I'd reduce the quality even further to about 70, no one will notice. The ppi (not dpi) is irrelevant here.
The factor that affects the file size of jpgs the most (apart from pixel dimensions and quality setting), is image content.
An image with large, flat areas will compress to a small file size, whereas an image with lots of busy detail will result in a much bigger file. Excessive sharpening and noise will also add to the file size.
The difference in file size can be quite dramatic - see the two images below, both exported at 80 quality.
For more information about the jpg format (and other formats), see File formats
Exporting with metadata set to Copyright only should add very little to the file size.
Thanks so much Per...and everyone...very helpful.