Question : Joomla's secret in Configuration.php

Today I went to install a new site Joomla 1.5.20 and noticed when I went in to the configuration.php file  to put in relevant information and it showed a var secret line. Shown below on the right. It stated to "change this to something more secure" .
I looked back at another site for reference. 1.5.10 was the original version. The site has been updated. That configuration.php secret is as listed on the left hand side of the image.
1. Was I supposed to change the original 1.5.10 install to something else or leave it alone. It looks encrypted.
2. Is that tied into the user password on the site in some way and if I change it in the configuration.php could that screw up the login credentials accessing the site?
3.Also now that I have exposed them on this site should I change them again for a safer more secure website? Have I exposed myself dangerously at this point?

Please advise. Thank you.

Attachments:

JoomlaSecret.png (3 KB) (File Type Details) 

secret encryption

Answer : Joomla's secret in Configuration.php

update LocationContributions SET mDateTime = DATEDIFF(d, 0, mDateTime)