We've been building JomSocial Business Pages for a while. Now we publish new modules to ease the task to build directories.
In a nutshell, JomSocial is a Joomla-based platform for building social networks and community websites with collaboration tools, Facebook-like features and more.
When a social network reaches a tipping point, companies ask for a space to properly be there. If there's no space, users tend to create fake users as a way to promote their business. In 2009, Facebook introduced the Pages, and Google+ Pages were introduced in the past year.
To show you a success case, Contablicos.com is a professional social network, with a business directory:

Our recipe to build a Business Directory, we prefer Sigsu's SobiPro. SobiPro is a powerful directory extension for the Joomla! Content Management System that is designed to easily create multiple directories or content types. SobiPro will allow you and your site visitors to submit, search, filter and view custom content on your Joomla! powered website with ease.
There are well-known directory components (Mosets Tree, Adsmanager, or the old Sobi2); however SobiPro has a dynamic field structure along multiple directories.
After we install SobiPro, and customize the directory; we want a tight integration between SobiPro and JomSocial. So, we've developed and tested in our projects a JomSocial and SobiPro application.
With these apps, we have two great components, and a perfect integration between the social network and the business directory. In the next post, we are going one step further with JomSocial Widgets (coming soon)!