You can use a service like Google Analytics, you add it in the footer of every page of your website and it will keep track which pages are accessed, what links people click to leave your website and so on.
Alternatively, write a small php script that tracks the clicks in a database. For example, create a table with 3 columns : unique url id, click count, url ... optionally you can also add the logged in user id or the ip of the user.
Add the url in the table and it will get a unique ID, for example 12345. Then, instead of writing the url in the post, simply say yourwebsite.com / yourscript.php?link=12345 or yourwebsite.com/redirect/12345 (a configuration setting in apache will change redirect/12345 to yourscript.php?link=12345, see mod_rewrite for example)
When user clicks on link, script loads, retrieves the url from table, increments the count and then redirect user to that url.