It took me awhile to notice that feature too. Probably years.
Maybe it’s because I’m from the DOS days, so typically don’t hover as a habit, especially since FR is generally text. I’ve known about the hover feature in other applications for many years.
Also, unlike nowadays in email where you’d click on a name to reply, the FR reply is to the left of the line after the poster’s name. So if I wanted to reply, my mouse never had much chance to linger over the name.
Going through the article list, I did have occasion to notice that the OP’s name would immediately underline, which was a clue to stop the mouse. You then see the link to their page. This underline bit does not occur where you have article comments, so was a contributor to my not noticing, as the hover text has a delay before appearing.
Plus, the way I generally act with the FR UI is to open a post in a new tab. Thus, my mouse goes to the tab to select it. Reading, I either go to the scroll bar, or simply use the wheel, whereby my cursor is going down the center of the page, never traversing names.
Nevertheless, I did eventually discover the hover through some, possibly random, sequence of events that I cannot fathom.
People used to claim that if you get one of those quick chills and shudder, for no apparent reason, it means someone walked over your grave.
This makes me wonder what effect hovering over a user name has on the individual. Maybe this is why I occasionally feel the need to scratch my ass.
I hope you enjoyed my beating this horse to death.