This is a general help for the system.
What an Url shortener do?
The URL shortener does not exactly short the url itself. It takes a long url address put it into database and assigns to it a short number like 256. Then it make an url like http://slink.pl/256.
What happens when a short link is clicked?
When a link like slink.pl/256 is clicked the system search an id of 256 in a database. When the record is found it takes the saved long url and make a 303 redirect to a given address.
What else happens?
After the click a additional things happens. The system check the IP and some other user specific information like browser and language. It save it for further statistic.
Our system does just a 303 redirect. It does nothing else. Please keep in mind that some url shortener before redirect your users to a long url save a lot of cookies like Amazon affiliate, or just show a redirect page for couple of seconds with some AdSense advertisement.
Some url shortener before redirect your users to a long url save a lot of cookies like Amazon affiliate
How long the links are kept?
There is no time set for removal of links. But it always can be changed.