Why google put my new niche site to sandbox?

You expect a site to be indexed and given immediate page rank so your site comes up on page one? That's funny. Very funny. You can't be serious, can you? Who told you that would ever happen? There is nothing under the sun that is impossible except when you cross the line into unreasonable and that is what you have done. Beautifully well done. Bravo!

my domain is [Your Goldmine Niche] dot net Excellent choice.

use wordpress to build - Serious webmasters don't build websites using blogging software. Blogs were not originally intended to replace websites, they were supposed to be used for daily updates to the websites they were linked to. Blogs morphed into Websites that the masses use for authority, value, money makers, atm cash cows, spam, directories, you name it and there's a blog right in the middle of it.

I submitted to digg, use ping dot fm to ping some social network site such as facebook, twitter, Tumblr, etc..

NO, NO, NO Pings without a cause! Pinging new sites is an obvious call for attention without any merit. Do you have something important to say that helps anyone other than yourself? What do you want to be on page one for? - WHY?

Do you care if your neighbor down the street gets that raise he wants? No? What if 1/2 that raise belongs to you? Then you would care enough to help your neighbor get that raise.

Google says, oh look. This guy wants us to put him on page One because look we see original, unique articles, etc.. he wants to help his neighbor get that raise he wants. Google doesn't know you're getting 1/2 the money unless you tell all your Facebook friends or tweet about it.

Now your reason has merit and Google adds that to their algorithm. The point is when you help someone else get what they want, then you will get what you want. That's how it works.

I also created a page on suidoo - Okay

Does your description and tag line say something like this? I don't even have to look to figure out the answer is NO. Why not?

Do you really want me or anyone else telling you what you "should have done" or would you rather just start doing it now? If you do, then let's make you into a case study and see what happens. Whenever something sets you back, turn that into something even better than what you had originally planned. How?

1) Build a REAL authority website or you won't do that specialized niche any justice.

2) Take 60-seconds and build a Wordpress blog on a sub-directory of your website and "act as if" you have authority and pretty soon you can drop the act. You have to act like what you want to be now or it takes too long to get there.

There are more steps you have to take but doing everything alone is the reason why everyone misses some steps and does other steps over and over again. You can't be afraid to be different unless you really don't want to be different. Everybody wants to have money but nobody wants to be different. You can't have it both ways. Learn to be different.

If you can find 6 more people who are ready to be authorities, then come on and just do it. I've got a full tool shed whenever you're ready and it won't cost you a single cent. Don't let fear take over just because you don't understand why it won't cost you anything. See if you can relate to the real secret of success. http://wealthlpp.com/realsecret and it's not FAILURE either!!!

All the linking you're doing now is worthLESS than if you spent that time building a real website that PR6 and above sites in the same niche will link to you. Sites like www.cell.com and others in that community. You have a gold mine and your're treating it like everyone else treats their tarnished $1 adsense blogs on steroids that will never shine right!!

I appreciate your point~

There are many ways in internet profiting, what you said is long-term, very safe kind

More people choose short-term way, including me...- -

Because if a real site can be built so easily, there will be lots of big sites now, but there isn't...

by the way, I don't understand this part "find 6 more people who are ready to be authorities"...and what's your tool?

You don't seem to have any significant links to your site at all so it's no surprise that it isn't seen as being a credible, important, site. Google's algorithm sees it for what it is, a Made For Adsense site, and is ranking it accordingly.

I believe the famous sandbox is just a myth, my suggestions would be to build more high quality backlinks.

The second problem for going out of the first page would be that your site is loading very slow, and you can get penalized by google for this. I am using Firefox 3.6.3