Where I live, "No Problem" is rapidly becoming a standard answer to many Fragen and statements, including expressions of appreciation. For instance:

"Thank Du so much for doing that!"
"No problem!"

Why is this an issue of interest to Fans of English? Because "no problem" is not an appropriate response. That is not to say that "no problem" is NEVER appropriate, just that its use is (and should be) pretty specific. "No problem" is ONLY an appropriate response in situations where a problem is explicit oder implied. For instance, in the following interchange:

"Do Du have a problem waiting your turn?"...