In order to recieve radio signals we need an aerial, usually a tv aerial to recieve signals an convert them to audio through our stereo in home or in a car stereo.
This is terrestrial reception.
Radio signal beamed to a satellite in space, this then sends the signal to all he homes with a subscrition and a satellite reciever dish
In the UK this is normally your SKY dish b there are others which recieve foreign channels to.
This is satellite reception.
Streaming means watching a video or listening to music in 'real time', not dowloading a file and watching i later. It is quite a recent development because your broadband has to run fast enough to show the data in real time. Files for streaming are usually highly compressed to use as little bandwidth as possible. Streaming has become really popular because of the popularity of the internet radio statios and various audio / video on - demand services such as spotify, last.fm, youtube and BBC iplayer.
On demand is basically a way of anybody to catch up on radio. It isn't live or shown at any particular time, so is avaliable to listen to any time and any where. It is also avaliable on different devices such as tv, phone or laptops.
Radio has changed a lot for the listener how we recieve and listen to the radio. It has changed for the best, because listeners can now catch up on what they have missed, on computers, laptops / tablets, tv and mobile phones at any time. It is still avalialbe to listen to the radio live from a normal radio.