That depends strongly on the company, doesn't it? A list of companies represented here after they get some usage would read like a "don't apply to" list.

That shouldn't be a problem. You have to already have a company email to view that company's comments.

But you can view the fact that people are commenting on a company. If a whole bunch of one liners suddenly appear as soon as the work day is over, you could guess that it's been banned at work and everybody's griping over it.