[Puzzled] Web 2.0 Indexed But Backlink Didn't Show Up

I've been making some web 2.0 site to back link my hompage lately. The content is spun from an article from an article directory. Got 1 link to my site in the article with a keyword that I want to rank for as my anchor text and blasted the web 2.0 site with SB. The web 2.0 site already got indexed and some of the link from the SB blast also got indexed. But when I checked back link to my homepage using yahoo site explorer the web 2.0 site did not show up as 1 of my homepage back link. It's been 1 week now, is it possible its because of the spun content or need to wait more?