To curb some of the questions that are going to come up for various self employment professions, and the consignment shop in general I decided to try to address this.
Right now, the consignment shop is a little buggy. Sometimes even with a very high rank in consignment sales ('skill' challenges completed) you will have a lot of items that never give indication they were sold. This doesn't seem to affect everyone, and only some of the time, but if you wonder what's up, you're not alone.
Also, sometimes consignment sales won't count toward a profession's experience bar. Sometimes, anyway. Sometimes it works, and sometimes it doesn't. And for me, it's moved a few times, but not others. Especially with bulk sales. That seems to be a problem. Unfortunately, if it's affecting you, you'll need to sell your Sim's items through the inventory screen. I'll update this if a patch addresses these concerns. I think the consignment store is going to be great once things get fixed up.