maybe it means: look out to the world?
It's means to look like you
"Here I come!"
it means you are going to jump into the day with a positive attitude and complete a plan.
well it's also announcing to the world that you are going to do something big. for example, people could use it to pick up their moods. when they have a job interview, and say look out world, here i come. meaning they have a good feeling about passing the interview. or something like that.