multiple blog working without weblog.absoluteurl configuration

Hello,

I read about setting up multiple webblog in roller and running them on 
different website. I previously was using [1][2] in my roller.properties 
file but when I did not use this lines and directly write rewriterule in 
my application for different website still it work fine. Is there any 
other use of this configuration ?

Below are rewrite rule I used in httpd (virtualhosts) file of both 
websites, as in both case when user hit the url /blog on different 
domains it will open different web-blog.

RewriteRule ^/blog(.*) ajp://localhost:7009/blog/test$1 [P,L]

RewriteRule ^/blog(.*) ajp://localhost:7009/blog/test2$1 [P,L]

[1] - web.absoluteurl.blog1=http://www.test.com/blog
[2] - web.absoluteurl.blog2=http://www.test2.com/blog

Thanks
Gaurav Saini*
***