perhaps the most surprising to me is the apparent willingness to enter credit card info online in 1999. I wasn't around for this period but wasn't the conventional wisdom back then that this was insecure? hence PayPal?
Average non-technical people used well-known companies, but that included eBay and Amazon. Presumably Network Solutions was trusted by this customer of theirs.
There were thousands of online shops at the time, selling everything that Amazon sells today, and it was common to purchase from them using CC or PayPal.