Consider this thread, for example, as a countably infinite sequence of posts (analagous to 0.99999…), but having only a finite length at any particular point in time. Let the completeness of this thread be designated by a real number in the range from 0 (that is, 0% complete) to 1 (meaning 100% complete).
Once the topic is discussed to death and beyond, it’s completeness resembles something like 0.9999… (for some finite number of digits). Each discrete post adds another 9 to the sequence, which thus converges upon completeness = 1, but is always some infinitesimal distance short of that. This post itself, for example, increases the completeness of this discussion from 0.99999…9 to 0.99999…99
By implementing an auto-zombie-resurrector event handling function and attaching it to this thread, we can have zombie-resurrection events queued automatically on some scheduled basis, which I suspect is what is happening here. Thus, this thread can grow infinitely in completeness of its own volition, asymptotically approaching complete completeness, but still always falling infinitesimally short.
According to ancient Hindu prophecy, when this thread reaches the state of perfect completion, then all posters, computers, the SDMB message board (indeed, ALL message boards), and infinitesimal numbers will all vanish, and in a great thunderclap the universe will end.