If it were "lot of prep" - e.g. a manually-tagged and fixed database of about 100,000 images of people pointing (assuming 100 columns and 100 rows in the browser-viewport) then that's still small enough for an instantaneous response from the web-server, so the relative long busy-time suggests that _something_ computationally expensive is running in the background - such as a "this-pointing-finger-does-not-exist"-engine.