Yes, the US military had a Don't Ask, Don't tell policy, and if you were found out or admitted to being gay, you were kicked out. But the repeal of DADT means that gays can openly serve in the military without being kicked out due to their orientation. And you are right, as far as the military services go, nothing too much will really change, or most likely wouldn't change. It's just a large step for gay rights, and now they don't have to lie in order to serve their country.