Supplemental v. Principal Registers. As you probably know one distinction between the two Registers is that all marks on the Principal Register are considered to be distinctive. Some were born distinctive -- think 'Google' -- while other more descriptive marks-- think 'Lean Cuisine' -- acquired distinctiveness via marketing and continued use (known as "secondary meaning"). When you apply for registration on the Principal Register -- yes, you must apply -- the examiner starts with the presumption that after five years of continued, exclusive use, the mark has acquired secondary meaning and is distinctive. (In legal terms, the five years of use amount to prima facie proof.) However, the Dear Rich Staff notes that despite this presumption, a trademark examiner, if doubtful of your mark's strength, can always require additional proof of distinctiveness. If we were a betting blog, we'd bet that your mark will soon make it on to the Principal Register.