As of now, 19% of spankers have actually sent a linkspank. This percentage includes those individuals who merely sent a spank as part of a tutorial.
I had been estimating the figure to people as 10%, so it was nice to find that the truth was shinier than my expectation. But the most important question might be whether 19% is a great figure or one indicative of some failure.
I believe it's a good figure. It's much higher than the percentage of users of other user-generated contest sites that actually are generating the content. (The comparisons are difficult because not everything is obviously comparable but I still believe that statement is true.) And the number will go up, by virtue of user experience improvements and consumer awareness of the spank.
Of course, 19% is much smaller than the % of people who have ever shared a link by email or IM (north of 90%). We have a long way to go toward being as used as email and IM :-).