Adding a discussion board/ blog

[kobra]

SHOULD i make a subdomain to link the board or blog to:
i.e: www.classydesires.com/blog
www.classydesires.com/discussion

Added folders would be
www.classydesires.com/blog
www.classydesires.com/discussion

SubDomains would be
www.blog.classydesires.com
www.discussion.classydesires.com

is this the easiest way to do this with no interfearance on my page other than adding a link to it?

Either way is acceptable and little difference

Also, my customers have obviously an account log in to shop.. can they use the same login s for the boards or must they use new ones?

The only "bridge" to allow this is for the forum script version phpbb2

[chachab]

The only "bridge" to allow this is for the forum script version phpbb2

Sorry.. what is that?
i downloaded SMF as my discussion board and Wordpress as my blog

[kobra]

i downloaded SMF as my discussion board and Wordpress as my blog

There is no published bridge for either of those

A bridge is code that sync's the user details for account login