YupRocks.com was originally created by Brooks D. In 2014 he turned it over to entomologist/naturalist Randi Jones, who added more images, more articles and updated the content. Here's a great article about Brooks, the original YupRock guy:
Story About the YupRocks Name
Brooks attended Calvin College and studied geology from 1996 to 1999. There were very few geology majors at the time; in fact, he graduated in 1999 as one of only two seniors who majored in geology. The department was very small. He found this to be a great benefit because they were given personal attention by geology professors, and were on the receiving end of some great teaching.
They decided to create a department tshirt and began meetings to discuss ideas. They agreed it should say Calvin Geology on the front of the shirt, but couldn't settle on what should go on the back of the shirt.
Most people wanted something humorous, but no one could agree on whether some ideas were humorous enough. After some discussion they went home and thought more about it. That was when he had the idea for "Yup...Rocks".
To come up with the idea, all I did was think about a question that people have been asking me ever since I started collecting rocks and minerals, and had begun studying geology. What is this common question? Typically it would start out like this:
Friend: "So, what are you studying at Calvin?"
Friend: "So, you like rocks, huh?"