W3Counter is the most powerful traffic counter I found. It tracks almost everything you need to know, like unique visits, search terms, locations of visitors, referrers and more. There is a Live View page showing real time data, such as Online Now, Twitter Mentions.
W3Counter offers free and pro accounts. As free account, you can track 1 website and up to 5,000 page views per day.
You need to sign up to use W3Counter service. After sign up, enter information of your website to create the counter:
Here is your tracking code, paste it on your website.
If you are using WordPress, you can install the plugin of W3Counter. Search Blog Stats by W3Counter plugin and install it.
Go to Settings, find W3Counter, Enter your website ID and W3Counter account information.
You can now check out your stats report on W3Counter or directly on WordPress Dashboard.
Load Impact is a new online service that allows you to see how much traffic your website can handle
Load Impact generates simulated user traffic to your site – for example it might simulate that 50 users are trying to load your web pages at the same time. While simulating the traffic from these 50 users, it also records how fast pages are loaded from your server. This lets you know how fast your site is (as experienced by a user) when it is being accessed by 50 users at the same time.
To test your website, enter your URL on the front page on Load Impact, click Start Test. And then choose Start Free Test:
You will get your report, after the testing is finished(it takes several minutes). As free test, Load Impact will test up to 50 visitors to your website. Here is the test report of ZackLive.com.