QuantCast, as noted in another answer, is an external site that provides statistics.
In addition, users who have earned the "View Analytics" privilege (5k on beta sites, 25k on graduated ones) can view SE's site-analytics page (this link is for MSE). This shows posts (broken down by questions and answers), traffic, and votes. If you don't have enough reputation to see this, you can ask someone who does -- sharing screen shots for a constructive purpose like building the site is ok. If your site is too new to have anyone with enough rep, you can ask a moderator. If your site is too new to have moderators, you'll probably have to wait a bit longer.
You can ask on your site's meta for data that your community can't get itself, but your focus early in beta should be on building the site, not worrying about analytics. I know that's disappointing to hear, but the data will come in time -- until then, make a site that people will want to visit.