I have an option on my hosting: "Enable dynamic subdomains?" Should I enable this? Any comments like why good or bad?
i think (but not sure) it would allows virtual sub-domains to be set-up, like scripts can make sub.domain.com apear to be a sub-domain even if it dont exist. kinda works in a similar way to how mod_rewrite makes urls.
What is purpose (or effect) of dynamic subdomains? I mean why should I set up them? My existing subdomains will become dynamic or...?
i dont know you will have to google for an answer, but the benefits would be i guess, if your hosting only allows x sub-domians you can bypass that or some multi-user scripts that offer free hosting of some sort use domian.com/username when they create a new account but with virtual sub-domains you can create username.domain.com without having to set up the sub-domain first.