On the Web: to add a friend, first be sure you are logged into your account. Then go to his or her Twitter page and press the "Add" link in the "Actions" box. To find a user page, use the search box on your own Twitter page.

Once you click "Add," you'll start to see his or her Tweets on your page if his or her account is set for public access. If the account is private, the system will send a "friend" request that must be approved before you start to see updates.

You also can see who your friends are following by hovering your mouse pointer over the pictures in the sidebar on your friends' pages. Those pictures are of their friends--the users they are following. If you click on one of those pictures, you'll go to that user's page, where you can add him or her, too.

You can see all the Tweets from any person's friends by clicking the "With Friends" tab above his or her message window. Or you can turn that off and see only his or her Tweets by clicking the obliquely named "Previous" tab.

On the phone or IM: send the command follow username to register your phone or IM account to receive public Tweets from a user. You also can invite people based on a phone number: SMS add phonenumber to 40404, and you'll start following the user at that number; if the person at that number isn't a Twitter user, he or she will get an invitation to join.

Managing your friends is much easier by using a full Web browser, but you can do everything on a mobile phone if you wish. See this page of the Twitter Help file for full commands, including details on the all-important Leave (to stop following) and Drop (to remove from your friend list) commands.

Want to be a Twitter nag? Send nudge username and they'll get a request to send a current Tweet.

In case you were wondering what the numbers mean...

A bunch of numbers are on your Twitter page. The most important figures are these:

• The number of "followers" you have. These are the people who are paying attention to (following) your Tweets.

   

• The number of "friends" you have. This is the number of people you are following.

Public figures and Twitter celebrities will have more followers than friends. People who want to watch more than participate will have more friends than followers. People who just use Twitter to communicate just within their own social group will have roughly the same number of friends and followers.

Person-to-person Twittering

You can send a Twitter message directly to another Twitter user with the Direct command. Enter d username message, and users will get your ping if they have direct messages enabled on their phone or IM account.

If you enter a Tweet with @username at the beginning of it, your message is understood as being intended for that particular person, although others will be able to see it. (However, @ tweets won't show up on your home page unless you are the intended recipient.) Be sure the person who you want to see your message is following you, or they won't get it.