I am thinking about adding a Blog to my site and I want to know if it can be on the same domain as site or if it has to be subdomain. Please help.
You can only have one index, so www.website.com will lead to only one page. Subdomains work but the best thing is to have a link on your main page (if they are related) or have a simple subdomain like www.blog.website.com Max
Publishing Blog on a subdomain or subfolder is not any problem, you can do this on every option you want, but there are more options and settings for a subdomain from than a subfolder example you can associate FTP account, web users and ... for a sub domain see you will need this settings with a blog or not? and publishing in subfolder may does not have this settings and.. and you can please me here>> forums.digitalpoint.com/showthread.php?t=490385
A subdomain seems more professional in cases like yours. Otherwise no problem if it's on a new domain or a subdomain.