In my experience, that site is ineffective. I used them once, and did not get results. Nowadays, yahoo, at least, marks all their posts as spam. They appear to be yet another poster child for a site that mismanaged its mailing list.
Thanks for your response. On a very limited budget, it's hard to know were to promote. I am doing sponsored ads and have some sales from that. However, getting it on the first few pages is very costly and odds are that it will cost more than it will make back. FROWN.
Welcome to the real world. There are literally more writers than readers on the Zon. And the number of writers is increasing. If you hoped to make money here, disabuse yourself right now. The overwhelming majority of indies lose money. Those foolish enough to spend a lot, lose a lot. Those smart enough to spend little, lose little. This is a hobby. The odds of it becoming a career are up there with the odds of your wining the lottery.
As for promo sites, Alexa is your bestest best friend. After that comes experience. There is no substitute for that.