New Updates/Status' Etc

[aceband]

Hey,

 

I'm trying to work out in my head how site'es like facebook show users wether other users have updated their status/uploaded more photo's. Does any one know how they do it - the brief outline of how it works?

 

Just somewhere to start em off....

 

Many Thanks

 

Chris

[ignace]

SELECT users_username, tweets_tweet
FROM tweets
JOIN users ON tweets_users_id = users_id
WHERE tweets_users_id IN (
    SELECT followers_followee
    FROM followers
    WHERE followers_follower = 1
)
ORDER BY tweets_tweet_date DESC;

 

Which shows all statusses of your friends: http://webdevkid.files.wordpress.com/2009/03/twitter-clone.png?w=536&h=376 (don't mind the text)