If you need to pay people (even with things like contests) to your site you're attracting the wrong kind of people...

Maybe there's just no interest in a site like you're building, maybe people can't find it that do have interest.
Word of mouth is the best way to get people who are passionate about your ideas.

harishankar;
I looked at your site today and I see after all the posts you have received, that not much has been changed.

I have to be up-front and truthfull so don't take this personal. I'm saying these things not to hamper you or offend, but to slap you into attention.

I don't feel sorry for you, I feel sorry for me and for any other visitor that would visit that mess. Visually, its a joke. Its' nothing I would ever join and I'm book lover. You have no headlines for anything. Quite honestly I could fart with more clarity because your site isn't clear. I cant tell if your comming or going theres no clear direction or objective. If you asked me to summarize your sites meaning, I'd respond with ?????????????????????????????????????????
All that said.

I can see that marketing that site would be easy. In fact if it were my project I'd have a 1000 new members in the first 6 weeks.

So rather than try to give you a lesson in marketing pay attention to this test that our group conducted in California USA. (no detail added for security reasons)
=====================CASE EXAMPLE=======================
The Situation:
In the United States a man was convicted for killing his wife and unborn son. The place was Modesto California. The case was well covered by the media.
Truly ripe for a test. We asked, How can this guy be convicted of murdering the unborn when 5000 women kill the unborn every day in the US? This was ideal to get traffic to a forum.

The Project Assignment:
Coin on the events that surrounded the case and spur controversy to guage belief patterns. What do people believe and why?

The Method:
Public Forum,

Details:
We placed a few free articles along with some paid ones in several small rag-sheets in northern California. Simple headlines that followed were;

"How to Out-Fox the Foxes", 50 legal tricks attorneys don't want you to know!
"Slavery Returning in the USA" History Repets itself! (Picture of chained man)
"Is Mass Murder Legal?" #####################
"How to Get Away With Murder" ####################

And there were many others specific to the case mentiond above but we'd rather not repeat the headlines.

Each advertisement had some small vague details, just enough to get people to visit the forum we posted. In 3 Weeks 2200 people became registered users at the forums. Controversy is an understatement. People took real emotional envolvement in the forum before we took it down a few weeks later. In the five weeks it was up the site had phenomonial traffic. We blocked all bots, made it public password accssed, and no advertising in the forums.

It got so out of hand that, members were threatening one another, Blacks went i-rate thinking the slavery article was directed at them when in fact it was directed at the corporate ownership of prisons. (Its getting hard to arrest good help these days) and we likely had more cops and attorneys sign up than I'd ever seen because of the Outfox the foxes article.

=======================================================
You need to write better headlines for your books in review. You need to create some reason for visiting your site above and beyond book reviews. Thats about as exciting as catching syphilis. Give something to your visitors and give them a COMPELLING REASON to visit. More important a COMPELLING REASON to JOIN.

Only My-Two-Cents
Jared

So, people are trying to help you but instead of listening to their advise you say "you're all wrong, I am perfect, my site is perfect, and people are just stupid for not realising it".

With that attitude it's little wonder people aren't flocking to your site in droves.