No, a dash does not protect any name. abc, abc.com, a-b-c.com, a-bc.com and ab-c.com are all what would be termed "confusingly similar" to a trademarked name. That being said, unless your domain name is the same as a registered trademark
AND you set up a website to compete with their business, I wouldn't worry too much. Take the three letter acronym ABC. Worldwide there are probably thousands of entities using ABC as their acronym in an unregistered state. For registered TM's a trucking company could be called ABC, a bookstore called ABC, a broadcast company ABC, a toy company, a pharmacy, and on and on. The same thing with FAA. If you look on the internet FAA.com has a computer company, FAA.net a automobile association, FAA.org an Adventist academy, FAA.gov Federal Aviation Administration, and, I'm not even going into all the individual country codes. On another note there is nothing wrong with having a website titled FAA and posting pet supplies or a blog. You registered the name and can do with it as you please. Sure, if your site makes a million dollars, someone, somewhere in the world might complain. But, if you made a million dollars you could fight their assertions.
Because of the nature of acronyms, they are very hard to prove infringement upon. FAA could stand for hundreds of things. And, if a company wants your FA-A but only registered FAA the judge will ask them why they did not register it or use it actively in commerce. Coca-Cola and Wal-mart both have registered their dashed names.
A little more advice...You could always state something like FA-A can't be trademarked like FAA because both FA and A are words in the dictionary and the dash merely separates the two words. If someone tries to say that your name is not being actively used in commerce show them the receipts from your parking account. You've made an investment into your name, you've turned it into a business, your making a profit off of it while it's parked at various services, your collecting research on traffic, hits, monitoring it, adding keywords, optimizing it, renewing it, etc.. If that's not using it in commerce, I don't know what is. Thus, you've got just as much right to use it as the next guy...that is unless you knowingly set up a competing business. Then, just hand over the name with an apology.
This is rare but...
If an acronym is widely known and used by two very large organizations, and one is tarnishing the image of another, a judge can force one user to give up their trademark.
I recall this happened with WWF. World Wildlife Fund and World Wresting Federation both used WWF until World Wildlife Fund brought a suit against World Wrestlers for trademark infringement. There were many wrestling "scandals" and controversies at the time of the suit brought by the World Wildlife Fund, so tarnishment may have been a deciding factor as WWF had to change to WWE.
