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.
99Counters offers real time traffic counters for free. It counts Daily Visits, Total Visits and Online Visitors with country flags. You need to sign up to use its service.
Here is a demo of traffic stats report.
Get Your Free Counters
Alexa Traffic Widgets are official tools from Alexa. They are very easy to use, just enter your website/blog URL, the widget code will be given to you. And paste it wherever you want on your website.
There are three widgets: Alexa Traffic History Graph, Alexa Traffic Rank Button and Alexa Site Stats Button.
GET Your Alexa Widget
Trendcounter offers free Real-time traffic counter widgets. It’s similar to RadarURL which shows online visitor number. Trendcounter also has a flag counter separates visitors by country.
All Counter Widgets are free of charge, adfree and immediately usable without signup. On your Website, Blog or Social Network profile.
With our realtime stats you’ll see who’s online on your Website. They are so much more than simpleOnline Counter! One click on the Widget, and you’ll gain statistics of your visitors in the history.
Get Your Real-time Flag Counter from Trendcounter
RadarURL is a real-time counter widget. Using the RadarURL Widget, You can count the number of online visitors, see where they are from (on a map) and where they are right now on your website.
Installing RadarURL widget is a easy job. Choose the position of the widget, copy the script and paste it on your website before the </body> tag.
Here is how it works(I chose right bottom).
Get Your Own Real-time Counter from RadarURL