Different people use Twitter in different ways: a news source, a chat room, forwarding interesting links, crowdsourcing information like Twitter Vote Report, staying in touch with friends, meeting fans and potential fans, and so on. It can all be a bit bewildering at first.

A couple of good starting points:

Deanna Zandt's Why Twitter, anyways? and A non-fanatical beginner's guide to Twitter. David Pogue's Twitter is what you make it Howcast's video How To Use Twitter (to the right): Twitter also offers a FAQ and a help page of their own.

Terminology Basics

@ replies

Use an at sign (@) in front of a Twitter username to reply to someone, to refer to them, or direct a new message to somebody. So, for example, the tweet

@gregpincus check out the new page @jdp23 has up at http://bookpromotion.wetpaint.com/page/Twitter

tells gregpincus to look at jdp23's page.

You can see all the tweets directed to you by clicking on the @yourusername link when you are signed in and on your "Home" page.

Retweeting (RT)

Retweeting is the act of sharing someone else's tweet with your followers - spreading the word wider. To identify a retweet, the Twitter convention is to put RT at the start of the retweet and to include the Twitter username of the person you are retweeting (like attributing a quote). So...

RT @SCBWI Our summer conference is August 7-10.

would be retweeting an @SCBWI tweet announcing conference dates.

Hashtags (#)

Use the sharp sign (#) as part of a "hashtag" to organize and categorize your information. For example "skittling and fiddling" sweeps poetry awards despite not rhyming! #poetry Whether or not you've got an account there, Twitter hashtags are an easy way to follow conversations about different topics. You can follow them via Twitter Search, RSS, Friendfeed, or clients (see below) like twhirl and Tweetdeck. "An Introduction to Twitter Hashtags" has more, as does Mari Smith's video on the right. Book-related hashtags include ...

#kidlit - for children's literature

#YA - for young adult literature

#poetry - for poetry

#writing - for writing in general (resources, tips, questions)

Clients

Instead of using Twitter.com or their phones, many people use "clients" - standalone applications like Tweetdeck, twhirl, Seesmic Desktop, tweetie, or many others - to tweet and read others' tweets. Clients offer different user interfaces designed to make things like tweeting and retweeting easier, and some offer different ways to group the tweets you read. Once you are up and running in Twitter, it is worth checking out a client or two to see if it will make the experience more fun for you.

You can find links to many of clients (and other programs) at the Twitter downloads page.

#followfriday

Every Friday (and sometimes other days), it has become a Twitter "tradition" to recommend users that others should follow by including their username and #followfriday or #FF in a tweet. Sometimes you'll see a tweet full of usernames with no specific reason for the followfriday recommendation whereas other times you'll read a "why" as well as names. Looking at the recommendations of people you enjoy on Twitter is a good way to find new people to follow. Likewise, recommending tweeters you enjoy helps them get more followers.

The Fail Whale

Twitter sometimes reaches overcapacity and you cannot tweet or read tweets. When that occurs, users of Twitter are taken to a screen that includes this graphic (by Yiying Lu) of a whale, now referred to as the Fail Whale:

URL Shorteners

Because of the 140 character limit of each tweet, it can be difficult to include full URLs in a message. Even this page has a URL that contains 45 characters... or nearly 1/3 a full tweet! Luckily, there are many services that can take a long URL and give you a shorter one, usually under 20 characters, to use instead.

Two of the best known sites are Bit.ly and tinyurl. To use either, you go to the site, paste your long URL in a box, click the "shorten" button, and get a new, shorter URL that you can then paste in your tweet or in e-mail or wherever you want. As an example of how it looks and works: http://bit.ly/8w5VR is a shortened link to this page.

This post on Go2.me offers up over 130 URL shortening sites, as well as a lot of information on how and why to use them.

Useful Lists of Twitterers

These lists are not likely to be complete resources but are presented as a reference:

YA Authors on Twitter (from @mitaliperkins and @readergirlz)
Middle Grade Authors on Twitter (from @taralazar)
Picture Book Authors on Twitter (from @taralazar)
100 Authors on Twitter (from @mashable)
70 Non-fiction Authors on Twitter (from @mashable)
Poets on Twitter (from @collinkelley)
...

Accessibility

The issues with twitter.com are not as crippling as an “all flash” site but these small details show when developers understand accessibility and have an attention to detail. Don’t get me wrong, twitter.com is far more accessible than a great deal of sites out there.

-- Nick DeNardis' post on eduGuru discusses some of Twitter's issues with accessibility,

Accessible Twitter is an application (still in the "alpha" stage) written by Dennis Lembrée that provides web accessibility for Twitter that works with or without Javascript. Items currently implemented include making all links are keyboard accessible, large default text size and high color contrast, and forms marked up for optimal accessibility. Follow @AccessibleTwitr for more.