Don and Harriet Chapman

From Homestar Runner Wiki

Don and Harriet Chapman are the parents of Mike and Matt. Don is a retired chief financial officer of an insurance firm. They helped the brothers run their website Store using their ping pong table as a command centre to fulfill order requests during the Decemberween sales rush.

They also seem to have a say, albeit a small one, in what is shown on the site. Marshmallow's Last Stand was temporarily put back on the site after several requests from Don Chapman. (See disclaimer at start of cartoon).