We just implemented a chat slider across our library's website
<https://library.ubalt.edu>, set to open automatically 10 seconds after
page load.  Although the slider seems to be increasing our interactions
with users, I am worried about a negative affect to usability or
accessibility.  NNG clearly says <https://www.nngroup.com/articles/popups/>that
pop-ups are generally bad, but the slider isn't quite a pop-up.

Anybody have some authoritative info on the usability and accessibility of
chat sliders?

Regards,
Kyle