MA resident. The biggest problem with this is the timing: tell us in July that it goes into effect on January 1, we can deal. Tell us it goes into effect in a week? Hah.
That and the fact that the line between custom software and customizations of pre-written software isn't very clear (or if clear, draconian). The way they wrote it, a custom WordPress template sounds like a customization (therefore taxable), but a site not hosted in a CMS is custom (non-taxable).