Gained popularity on manga/anime sites where the #--- visitor got a free drawing. That was the kiriban number or kiriban art.
Now it's being used more for an exclamation of achievement, as hitting the #whatever view of your website is a kiriban.
Mangapunksai hit the kiriban number on her webpage and will make a commerative piece of art because of it.
Baka-chan had a contest for whoever hit the kiriban number and will make a kiriban piece for that person, a gift art.
People came from all over to give kiriban to damphyr for winning the contest.
Kiriban to you for finding my obscure webpage!