(Internet, of threads on a bulletin board) Fixed at the top of the list of topics or threads so as to keep it in view.
(Internet, of a website) Compelling enough to keep visitors from leaving.A woman has come to me with the complaint that her website is not "sticky" - 70% of the visits last 30 seconds or less.
Of weather, hot and wind-less and with high humidity, so that people feel sticky from sweating.