In my site, I have links to tutorials by site which look like this: http://www.mysite.com/site/www.othersite.com/ so when users click such a link, they get all the listed tutorials by www.othersite.com. There is no real directory on my site called /www.othersite.com/ it's a virtual directory created and translated by php scripts and every thing is working fine so far but I was wondering: Could this cause me problems in the future (e.i. if I change the host, changed to IIS, new version of php....etc) Should I replace the dots with underscores or leave things like they are? What do you suggest?