Steven Zahm@ Jo
re: a company that wants to list in our directory would be set up with a user id and password and given a subscriber role.
Correct.
re: I can insert some code that would take them straight to the directory page when they log in.
You could use a user login redirection plugin to do the redirect the the directory page of your site. From there, they can click on the link to add their entry which will be displayed above the directory. If there entry already exists, then the link will show view my directory.
re: Am I correct in thinking that Link will take them straight to their basic listing
No, Link only links a user account to a directory entry to allow that user to maintain it. It does not do any login redirection.
re: does their email address need to be their user id for this to happen?
The email address in the user account must match the email address in the directory entry for Link to link the two.
re: they can use Form to add in the other details?
Correct, if Form is installed, they will be able to add/edit their entry on the site frontend using the same links that the Link extension adds. The difference is that the links will resolve the page where they can do it with Form on the frontend instead of the admin Link profile page. Hope that makes sense!