Hello,
Many stores still have a physical presence as well as an online store. Most products are still non-taxable for online purchases while products purchased at the physical store are taxed.
Apparently, there is no good way to make products taxable if the delivery method is "store pickup" in ShopSite.
http://support.shopsite.com/forums/viewtopic.php?f=1&t=10190
It would make sense to me if there was a feature to allow for this condition.