One feature of Discourse and not in vBulletin is the number of times someone has clicked on a link in a thread. But if you look at some of the older threads which have links in them, they frequently have numbers of attributed clicks that seem extremely unlikely to have been clicked after the conversion to Discourse. This would suggest that the number shown includes clicks when the site was still in vBulletin format, and that though this information was not displayed in that system, the information was still being collected.
Is this correct? And is it also true of anything else?
No, I think Fotheringay-Phipps is referring to the click-count for a link, not the view count for a topic.
Notably you will see a separate count for unread posts if the link is to a Discourse topic. If you’re looking at that kind of link you might have confused it for the click count. By default the unread post count has a blue background and the click count has a grey background. You can hover over the number itself and see what description comes up.
I’m pretty sure it’s true for a lot of information. I don’t remember a lot of the information on the profile summary page in Discourse being shown anywhere on vBulletin.
Just pulling a random post from my ‘how much do you read’ thread. Most of these stats are an aggregate from before the transfer. I don’t remember them being displayed on vBulletin and they’re now in the profile page of posters on Discourse.