I thought it was about eCommerce. It might be subtle difference but perhaps not. Posting a "for sale" note on usenet or a BBS and then paying for/picking up the item in person doesn't necessary qualify as ecommerce. Commerce yes, but not ecommerce. I think the transaction needs to take place electronically -- not just the "promise" to buy/sell.
We also had services like compuserve which allowed placing at least airline reservations (can't remember if they allowed outright purchases). Even that may not really qualify as payment was fixed to your account. Please someone correct me if I'm wrong -- I'm pushing the limits of my memory of a service I had ~30 years ago.
I believe the article is spot on with the CD sale being the first (or at least the first verifiable) "on line" purchase and the start of e-commerce. The payment type was selected (random credit card) -- the transaction was secure -- it was transmitted electronically -- received and funds transferred -- and the purchased item was delivered to the purchaser.
To argue earlier instances of "commerce" taking place using usenet or BBSs as a means to arrange the deal as being the first "ecommerce" is akin to saying the fact that light bulbs existed before Edison so what he did wasn't that important (other than take a wire that would glow for a few mins to a few hours and extend that to months and build it cheaply enough to sell to everyone and are now ubiquitous).