In the early hours of this morning, this site was the victim of trackback ping spam. I don't expect this to work, but let me make this clear to any spammers who may be reading this (yeah, right....)
1) You will not get google ranking due to trackback pings on this site (or any of its subsites). There are at least two measures in place to prevent this.
2) Your links will not last long, as soon as I notice them, I clean them up. Links to your site will then be blocked.
3) This site is quite low traffic, so you're not going to get much (any) human clickthrough.
In essence, you're wasting your bandwidth.