In this series I explain in plain and simple terms what various web 2.0 concepts and applications are. Items covered so far are Web 2.0 itself and blogs. This time, microblogs are under the microscope.

Microblogging is a form of blogging in which the length of each post is limited to a certain number of characters. Usually this is set at 140, but in some cases it is 160, the same as sms (text) messages.

So what can you use this sort of thing for? In other words, what's the point?

The best-known of these services is, probably, Twitter. To some extent, and certainly at first, its value was doubtful because, believe it or not, nobody really cares what you had for breakfast or that you're going to watch Neighbours.

But there are more serious uses. For example, teacher Chris Leach used Twitter to help his class of primary (elementary) school children understand the Gunpowder Plot, as you can read in the Web 2.0 Projects Book (2nd Edition) -- look out for that in the Free Stuff area of this website -- and in this summary.

Another popular use is as a means of recording what a speaker at a conference is saying, which can be especially useful to colleagues who were unable to attend.

It can also be used as what is called a 'back channel', which is a conversation between members of the audience about what the speaker is saying. Sometimes this can be quite useful, with people dropping in useful links and their own insights.

You could also use it in lessons, such as asking the students to have a meaningful debate through Twitter, or to write film of book reviews. It sounds impossible, but in fact the 140 character limit really focuses the mind and forces you to cut out excess verbiage. It also encourages 'sms-speak', which some educators do not approve of.

One of the most common uses of Twitter is to pass on information about useful resources. Indeed, I regard this as essential to my attempts to keep up with all the developments in education and educational technology. As part of this dissemination process, some people (including myself) use Twitter to announce the posting of new articles on their blog. You can use a service like Twitterfeed to automate this through the use of your blog's RSS feed .A school could use this facility to let parents know when something new has appeared on the school website. For this to work, you'd have to set up a Twitter account for the school, and then try to encourage parents to sign up to Twitter and then 'follow' the school.

Topics of interest can be assigned a hashtag, eg #myconf. By entering the hashtag, 'tweeters' can help to ensure that their post will be picked up by anyone keeping track of that hashtag.

Twitter also has a list facility, which enables you to join or create lists of people in Twitter whom you'd like to 'follow': following someone means that you are more likely to see their messages than if you weren't following them.

Twitter is not the only game in town as far as microblogging is concerned. There are two others which are especially suited to education, these being Edmodo and Cirip. Each of these allows you to create groups, which can be very useful, and its worth exploring their features to see which one is right for you. or example, Edmodo allows you to upload files, whilst cirip lets you include pictures and even video clips in your posts, and to create or join private groups. Don't let the fact that it's Romanian put you off: there's an English version of the website. ave a look at José Picardo's article on Edmodo, and the related articles he lists at the bottom of the page.

A moment ago I mentioned reviews. There's a service called Blippr which is specifically set up to enable you to review books, music and films in 160 characters. Moreover, it incorporates elements of social networking because you can easily see and interact with others who have reviewed the same thing. Obviously, though, this has implications for e-safety, as does any kind of open online space. The same applies to the similarly-named Blip, which lets you create playlists of music tracks, which you can also review, and connecxt with others who share your taste in music.

One last thing: the groups facility in Edmodo and Cirip could be used in the service of admin. I think if I were still a Head of Department I would seriously consider setting up a group for my team, to enable us to quickly and easily exchange notes, news, links and other resources.

In conclusion, blogging and microblogging are two very different, but potentially complementary, manifestations of Web 2.0.