Right. If you have raised a Memetchi and you plug the Memetchi figure into your Tama, then you character will run a shop. It'll also work with Kutchipatchi, Mametchi, Violetchi...
I have had this once and it happened with my Charmametchi. I thought it was cute but I did not understand how to use it. and so you're supposed to wait for a customer to come. And I didn't get any customers because of my stupidity! lol