A blog is a website in which journal entries are posted on a regular basis and displayed in reverse chronological order. The term blog is a shortened form of weblog or web log. Authoring a blog, maintaining a blog or adding an article to an existing blog is called "blogging". Individual articles on a blog are called "blog posts," "posts" or "entries". A person (student or teacher) who posts these entries is called a "blogger". A blog comprises hypertext, images, and links (to other webpages and to video, audio and other files). Blogs use a conversational style of documentation.

Vlog is a videoblog  which uses video as the primary content; the video is linked to within a videoblog post and usually accompanied by supporting text, image, and additional metadata to provide context.

Podcasting is the distribution of audio or video files, such as radio programs or music videos, over internet using either RSS or Atom syndication for listening on mobile devices and personal computers. A podcast is a web feed of audio or video files placed on the Internet for anyone to download or subscribe. Podcasters' websites also may offer direct download of their files.
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Often blogs focus on a particular "area of interest", such as ETWINNING or COMENIUS projects.

This communities are able to create a Network of Blogs easily. Have a look at 21Publish Web Services. There you can find a community homepage, where users can register and login, find blog entries or community news. Additionally there is a second layer with individual blogs of community members. Students and teachers of DigiSkills are able to join DigiSkills BlogNet.

Headteachers' international weblog
http://digiskills-schools.blogspot.com

Students` etwinning project weblog
http://e-competences.blogspot.com