how to use twitter? Can I post my comment on my friends twitter walls like facebook?

[Ameen]

Twitter is a microblogging service, like you can go on and on about yourself albeit in just about 140 characters, it is useful as most people use it, pretty accessible too. Twitter doesn't have walls, they just have their own timeline, you could send a @ reply to contact a friend or someone whom you follow or follows you. Eg: @ryan Yo man, lets hang out later tonight at the Pub. Here, ryan is your friend and is his twitter handle, if his name is Ryan and @ryan (the handle) belongs to Ryan Seacrest, your friend might have a twitter handle such as @ryanbutler or something of that sort.

You can see @ replies from a tab on twitter that says Retweets and lists out all of your mentions.
Eg: If your handle is @jack, if Ryan Butler posts "@jack Sure thing mate, see ya there" you can see that reply in that particular tab.

All the best on using Twitter. Have a blast !

if ya have any more doubts, hit me up @aMjAZzz