questions on tinyurls and/or alphanumeric strings in URLs

These days iam seeing too many sites displaying URLs with a long alphanumeric strings at the very end of URL.

Ex: http://www.domain.com/somedir/b12b8eec6584510c

When i click on the url, it takes me to a page and the URL remains the same. It doesn't change to name=value pairs or to target urls like that of TinyUrl feature.

How is this managed? How do they resolve such a long alphanumeric string and display the right html page for us?

Do they use .htaccess to breakdown this url into something meaningfull and then render the page?

I will appreciate, if someone on this forum can explain to me.
Thanks again
link

 

start here, then search like this too if you need more info.

and just put it all in a .htaccess in the www-root of your website..

 

Hi rene,
I will go through the stuff you pointed me to. I have quick question though?
Is this a pure .htaccess solution or some database backend is also needed?
I ask this because, i have to generate a unique alphanumeric string out of few name/value pairs (these are my business columns and i don't want to expose them) and then reinterpret back to these name/value pairs

Can it be done purely by .htaccess method?
Thanks
sri