These are terrible! The only traffic you'll get from these are curious clickers and bounces (unless you're targeting entrepreneurs). I'd argue that these sites have a negative effect, since you're skewing your numbers without getting any meaningful stats (where people are dropping out of the funnel, why people are bouncing).

Instead, get featured on small industry blogs and build up from there. A little press goes a long ways. In my experience, I haven't even had to pitch larger new sites after getting a couple articles on smaller blogs. They see the smaller posts getting mentioned on Twitter and reach out to write their spiel.