Art you have not offended anyone and I hope i didn't offend anyone by asking! I guess I was just curious as to it's meaning. 
I like your curiosity and "I'm just saying" is use across the US.
Found this one
http://www.examiner.com/Here is what some people say it could possibly mean:
The person wants to share information without having to explain it further.
It's really an attempt to make an extremely weak argument to make the speaker's point good in the face those who might argue against it.
The person using this term doesn't have to or want to invest any amount of critical thinking skills and logic to support the position or to offer an explanation.
So as to not offend anyone, or to place emphasis on the fact that it is an opinion being stated saying "I'm just sayin'" at the end is to curtail any arguments based on what was just said.
The general use of the post-positive "I'm just sayin'" is meant to excuse having said something impolite or inappropriate.
This is said after an editorial comment. The speaker doesn't want to be held responsible for the consequences or the proof to support his opinion.
This is a way to cut down on any argument or explanation about what was just said. Saying "I'm just sayin'" is to be used immediately after a distasteful opinion is given. No response is appropriate.
Like a rhetorical question, this is a rhetorical remark that needs no response.
I'm just saying 
