Podcast vs Radio

Any difference between podcasts and radio shows?

I mean, I am confused. And I am actually co-hosting a podcast. Since in Sweden, the swedish radio is having an app for their shows. 
And I mean. What is the difference between those episodes and podcasts. They are both found on Podcaster. I even think some begin by saying "hi and welcome to this podcast".

Is the difference that podcasts are just not bound to a radio station or big company?

Nope. That is not it. Since a lot of media groups and companies have podcasts. And they are big brands with a lot of money supporting their podcast.

It feels like in podcasts, people are not as careful with what they say. Since it is "just on the podcast". Am I right?

Like I wrote regarding streaming, this feels like the future. I am not sure how though. Because in some way, when something grows big there will be a lot of laws and rules made up just because of money. And money is power. 

Will we see companies owning the market? Radio should not disappear but on those radio frequencys it might be podcasts broadcasted.  For people commuting there will probably always be some kind of radio available. 
Or will the 4G etc simply be the only thing left?
From 4G you could stream your list of shows you have put together on a tracklist. And the towers made for radio should work for 4G as well?

Now most podcasts are living on sponsor money I'd say. Some are like I said owned by media companies but I mean the majority.

So if the trend of podcasts all of a sudden disappears. I bet there will be a lot of famous podcasters that will be employed by radio stations all over the world. Since they do apparently have the ability to get people intrested in what they are saying.