those social site links do help your search ranking.
Here's a Search Engine Optimization primer by an SEO authority, too much of the stuff taught by others is out of date or simply inaccurate.
http://www.seomoz.org/beginners-guide-to...
You are correct that there not many sources for 'free' promotion of your website other than social media sites. I advice you to use those as much as you can.
After that you should also engage yourself in some promotional activities so that rank of your website improves. It would not be an over night process though as it would require some time.
Considering the present scenario it would be wise to use the huge reach that facebook has to promote your online business. And it should not be a difficult task either.
You just need to create a facebook page related to your website (it will be your own property). After that you need to engage the users of facebook to your facebook fanpage which should not be difficult considering the huge number of people that uses facebook. Once you have enough number of users on your fanpage you can direct them to your website. You can ripoff long term benefits from this.
You should try on major search engines like Google and Yahoo, once you get top position in search engines then you can get flood of traffic free of cost.
I think I tried almost every single social bookmarking site, and I also tried many social networking sites, ex: Facebook, Twitter, Google + and more.
Can someone please recommend me places to promote my website?
Preferably, other websites that offer free promotion.
