They are generally free, but since they have limited space, not everyone will want to use one. If you need to write a lot, you might not want to try cram everything into a small space.
I will discuss three very different micro-blogs by going over their functions and the type of members that would enjoy using them.
With Tumblr, you create a "Tumblelog" which is a micro-blog where you can submit post by website or email. It does not have SMS or instant message. But, you can choose to automatically notify blog monitoring services such as Technorati and My Yahoo when you post a new message.
You can create six different kinds of posts with Tumblr. They are Regular Post, Quote, Link, Conversation, Photo, and Video. The post do just what the names says they do. For instance, you can add photos by uploading them to your Tumblr site or pull them in by using a link.
These six posts make Tumlbr very easy to add content such as videos, photos and RSS feeds from other sites. As a result some sites are just posts with just images, quotations or YouTube videos rather than actual content. While other Tumblelogs resemble other blogs with long written out posts.
Other features include "followers" who have added you as a friend and are following your posts. Also, Tumblr has a bookmark bar button for easy posting of website finds. You are giving the option of what category to put your new content in when you click on the bookmark button.
Last but not least, you can host your custom domain name on Tumblr. You will need to buy your own domain from a registrar such as GoDaddy. Once you have done that, Tumblr gives you instructions on how to set up your site. They suggest that you already be familiar with setting up websites as they do not have the staff to give personal help.
With Twitter, you only get 140 character per post. There is no multimedia such as photos or videos, only text. Your page options are also limited as you can only write one-line profiles. But, you can change your colors and background images.
The 140 character limit does tend to create a stream of conscious message. This might be useful for updates on traffic, weather, or airport conditions. Or you could receive a blow by blow account of your neighbor's yard sale. It is all up to the members and you.
What makes Twitter popular is that you can use it practically anywhere. You can post Twitter by website, phone or instant message. If you want to instant message, you can choose between different applications such as AIM, GTalk, .Mac, LiveJournal and Jabber.
Squidoo is a free social networking website that is composed of lenses that members create. You can build several pages and link them together or build single pages on many different subjects. If you need help on creating a lens, you can click on "build a lens" button where you will be guided step by step on setting up your lens. Or you can go to SquidU, a website, where your questions can be answered by volunteers and expert lensmasters.
Squidoo is really helpful in building traffic to your new website or blog. You can link your site into Squidoo pages which are quickly built up by search engines.
You also make money on this site through adsense ads that are placed on your site and through Ebay or Amazon modules.
When advertisers generate money on your site, you get a portion of it. Squidoo divides it up into three parts. One parts goes to Squidoo for running the site, second part goes to charity and you get the third part.
Online marketers love this site for driving traffic and high ranking in search engines among other things.
Who should use a micro-blog? Just about anyone. Give the flexibility of a micro-blog, you could just share your photos or videos if you do not want to write. Even if you want to want to write and prefer to write longer articles, you might consider a micro-blog as a complement to your blog or website.