An audio blog, usually updated weekly or daily is what is referred to as podcast. It is a program which is available for immediate download on the internet. Video blogs are very popular nowadays, and anyone who wants can make one. The slang term for it is vlog. It is, in many cases, seen as a private diary. More and more teenagers use this kind of communication to express themselves. As already mentioned, it can serve as a private diary, it can be a fashion blog, a school blog etc. If you have the need to say something about something you can do it via an audio blog. Create your own website, and upload the things you record. You can use it to send a message, to express your political opinions etc. In this world, where nothing is private anymore, this kind of mean of communication can be abused. One may be recorded in many life situation without the knowledge about that, and then being put online and ridiculed.
The name podcast was mentioned for the first time by Ben Hammersley in The Guardian newspapers, together other proposed names for this new media. Finally, it was chosen because it is a combination of the part of the word ipod and broadcast.