For-profit businesses are always free to contribute, respond, and help maintain pages 
about their business on a wiki. These pages are maintained by the community as a whole,
and the pages should be written in the voice of the community, not in the voice of the
business. Pages about businesses should serve to inform and teach the community as a
whole, not promote a particular for-profit business.

What's this mean? This means that adding stuff like promotional material (without any
other value, e.g. it's not historical, newsworthy or otherwise interesting) and
advertising is generally not okay on pages about for-profit businesses. We tend to
consider things like long product price lists to be promotional in nature, but there are
exceptions.