Used correctly, twitter is an amazingly good viral list building tool that can catapult your list from zero to thousands of followers in a very short time.
If you are interested in a particular niche, simply find some leaders in that niche and follow them on Twitter.
You can also look at who else follows these influential people and if you want to network with them, you simply follow them as well.
Because the Social networking etiquette is to follow back anyone who follows you, then your list will grow quickly.
By sending out interesting tweets, re-tweeting other people's tweets and responding to tweets sent to you, your list will grow even faster.
There are also some good tools available for automating the process in order to reduce the time necessary to administer your Twitter account.
It is advisable to learn how to use the tools correctly because otherwise you may be seen as a spammer and have your account suspended.
I recommend using Tweetlater to assist you with scheduling tweets to be automatically sent out for you when you are unable to send them manually.
I also use this tool to automatically respond to everyone who follows me on Twitter.
Be careful how you use this feature - I recommend you say something like "thanks for following me, I look forward to receiving your tweets and becoming friends".
So many people use this tool to spam followers with some business opportunity, but I personally do not recommend this - If the follower wants to know about your business opportunity, they can click on your website link in your profile.
Another great tool that I use is Tweetdeck because this provides fast access to simple reply, direct message and re-tweet tools which make working with your tweets a breeze.
This tool allows quite a lot of customization so that you can have the features that are important to you, just a mouse click away.
Always remember that your aim on Twitter is to be liked and held in high regard by other people who will want to follow you and read your tweets.
If all you do is blast out invitations to business opportunities or send out automated advertising, most people will not enjoy receiving your tweets and will un-follow you pretty fast.
If you have some exciting information that you want to share with others, then I recommend that you place this info on your blog or in Facebook and invite Twitter followers to read it there.
That way you are not spamming anyone, and serious networkers will be more likely to want to connect with you where they are not limited to 140 characters of text.
Another great micro blog site that I like to use is called Tipdrop because it has a strong business and useful tips bias.