In the software development industry in particular, the phrase in practice is used to mean true, in contrast to in theory, which is a patronizing way of saying false, but well-intentioned.
The phrase in practice precedes a theory just as much as the prhase in theory. In the best cases, it is a theory based on the experiences of many people, and maybe even empirical studies, and is likely true. But in the worst cases, it preconceived notion from someone lacking real knowledge of the "practical" theory and the more "theoretical" theory.
Don't use in practice or in theory as spin words to assert your idea as right or belittle the opinions of others. Share what you think and back up your position with facts and sound reasoning as much as possible. What you say works in practice is a theory, too.
Ok, enough italics for one day. :)