A little second-hand anecdata: my sister works for one of the big email marketing companies and from what I've heard from her the tagging features are a _big_ t

A little second-hand anecdata: my sister works for one of the big email marketing companies and from what I've heard from her the tagging features are a _big_ thing for customers. You could perhaps try shifting "tagging" to the paid subscription or somehow constrain the tagging on free plans?