I don't know what the difference would be... So I googled it and came up with this:
Marine 2 Stroke Oil VS 2 Stroke Oil: (Explained)
It looks to me like the main difference is the marine oil is an ashless oil. From reading bits from other sources, I believe that means no zinc in the oil and it translates to less deposits on valves and combustion chambers. It also looks like instead of using regular 2 cycle oil to replace marine 2 cycle oil, it wouldn't be a bad idea to use the marine oil in your chain saw etc. That's a bit of speculation on my part.