I'll take a bite and offer some suggestions.
When you write, "As for my niche, the website is generally open to all kinds of people, would best fit for an age group of 13-60," I hear a general lack of focus. You're basically saying that your niche is pretty much everyone which, by definition isn't a niche at all.
You also say that a primary target is people with privacy concerns. This is a very important group of people. That's your niche, and it includes people of all ages, which might be why you offer up a 13-60-year-old age range. Forget the age range though, and think instead of the product that you're creating and why those people might want it.
You mention "website" over and over again. You may want to rethink this. The Internet is moving quickly toward mobile and has been for quite some time. Facebook and Twitter are focusing their efforts on their mobile offerings.
Instagram, the social photo platform that's primarily mobile was gaining tens of millions of users very rapidly. Facebook bought it for a billion dollars. Instagram's revenue at the time? Zero.
Also, think less "site", less "destination" and think more of a "utility". As in that which makes information flow, sharing and social interaction possible. That which is the connective tissue that other platforms and initiatives build upon. Think APIs.
And remember that those in your niche, those with privacy concerns, are also very concerned not just what is done with their data and how it's mined, but they're concerned with their actual ownership of their data. They're concerned with the portability of their data. As in, if I stop using this or that service, can I take the hundreds or thousands of content objects (eg., photos, videos) and ideas that I've uploaded and contributed to the platform with me.
This is important. Google has their data liberation plans that allow you to do this. Others are following suit. But more importantly, smaller players are working too on trying to figure this out. Take a look at Status.net. It's a an Open Source Twitter-like platform but what's neat about it is that the distribution model is an idea of many federated sites. That is, anyone can launch their own Status.net instance and those instances (or sites if that's easier to understand) can speak to all other instances and receive and share content and messages across them. Important though is that since you create and control the instance, you have full control over what happens with the content that you put on it.
Another interesting initiative is one that bubbled up in the last few weeks or so. It's called App.net and it just raised $500,000 in a Kickstarter type campaign to develop a social network that's based on open APIs. The founder's ideas behind it, and his disappointment with, for example, Twitter and Facebook can be read here:
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http://daltoncaldwell.com/an-audacious-proposal*
http://daltoncaldwell.com/dear-mark-zuckerbergGetting a little bit out of the weeds and outlining the potential significance of it all is this article over at GigaOm:
http://gigaom.com/2012/08/13/think-app-net-is-just-a-twitter-clone-then-youre-missing-the-point/Anyway, I could drone on, but hope these few ideas help you as you think of yours.