Part of the process of registering a Trademark involves advertising the application. This is to give people the opportunity to object and forever hold their peace. This is a crucial time to watch out for trademark scams as it creates a great opportunity for criminals and scam-artists to get and use your information and try to squeeze a few dollars from your wallet.
Professionals who register trademarks for a living know how to tell the difference between legitimate correspondence that requires a response, and scams that should be ignored. This is not so easy for anyone else, as scam correspondence is made to look legitimate, and contains your personal information. It is easy to mistake for legitimate correspondence.
These scams tend to find you when you are in the process of applying for a Trademark, and after you have had one registered. If in doubt, show it to your commercial lawyer for their opinion before taking any action.