@PaulWalters is right. The support for emailing in died some while back (thing it proved to have lots of unexpected challenges and very few used it). The one system integrated with Tinderbox is Simplenote (see more). There’s nothing special about Simplenote as opposed to other similar apps - it just happens to be one that has some integration with Tinderbox.
The link cited at to actually isn’t to aTbRef. It is to a very old proof-of-concept project I did, partly to learn HTML export and partly because the then-current manual was only in PDF form and (on the Macs of the time) I found it hard to use.
I generally leave public HTML resources up (or until that server dies) as it’s the moment you take them offline that angry people emerged from the undergrowth to complain because they use it. If I can find the source doc I’ll try adding a waring banner as I already do for the 3 (?) copies of aTbRef relating to older versions.