That really is a good link.
I didn't realise that mites create a fine web
I don't mind having spiders around my orchids, because I think they will catch and eat pests, but now I have to take a closer look whenever I see a fine web because it might actually be mites not a spiders web!
Did you check out the photos of the mites? They are some weird looking critters
http://mrec.ifas.ufl.edu/lso/images/Mites/TU6.jpg