Live air (radio) disc jockeys have to have personality in order to related to the people who make up their listening audience. They are dependent on their listeners interacting with local advertisers and organizations in the local community. The web (Internet) jockeys at time managers, they are responsible for air ads on time and ensuring that they are in sync with their subscribing stations, no personal interaction at all.
As the access to the Internet increases, people are prone to switching their media choices to this medium. The largest reason is variety. In any local area the radio is limited to maybe 20 channels. Of those, there may be five that a person listens to regularly. The Internet has no such limits. Understanding that the massive increase in disk jockeys on the Internet provides some competition. Radio is still more readily available though. Internet DJ's are not necessarily paid for their services and thusly have lower standards. The typical radio station will have someone at the mic 24 hours a day. internet stations can have lapses in time with no DJ due to small staff. Radio is still going strong. So don't touch that dial.
Between the radio and the internet, radio disc jockeys are better.They go back to old school ways where they would spin discs the old school way.Radio disc jockeys also have to rely more on their wits and personality where internet disc jockeys can use technology to cover up their areas of weakness.
I think that the disc jockeys on the radio who have to talk live on the radio, pick and play music that everyone will enjoy listening to, and answer emails, messages, and phone calls from the listeners have a lot more talent that those that work over the internet radio.
There are far too many differences between the two mediums, and the internet and DJs can't really be compared. You can't just plug a computer into a speaker at a club or some other live show, while, at the same time, no DJ could have the variety of the internet.