Perhaps more important than the number of visitors that StumbleUpon sends me is the fact that it's a referring site with a very, very low bounce rate!
Mhlawumbe okubaluleke kakhulu kunenani lezivakashi uStumbleUpon angithumela lona iqiniso lokuthi yisayithi elibhekisayo elinezinga eliphansi kakhulu!