Yeah it uses,that's why twitter has a limit of 15 characters in a username.
Any tweets you write (which don't begin with an @username) will appear on your timeline for all of your followers to see. Anyone who also visits your profile (providing you don't have protected tweets) will also see your tweet.
She does have a Facebook & a Twitter; you can tweet her @snooki. She does reply to some of her followers, so give it a try!
You have to remember that a celebrity will have thousands of followers. It's quite possible that they just haven't seen your tweet. It's possible that you are tweeting them when they are not online and by the time they are your tweet is too far down for them to see as others have been tweeting them. Some celebrities don't really reply to anyone either. they do reply to you but sometimes they are offline
To add to a trending topic, simply write a tweet containing "#topic", where "topic" is the name of the trending topic. Replying to someone who has tweeted about a trending topic is no different than normally replying to a user; just start your response with @username. Alternatively, if you are using the twitter.com website, you can press the winding arrow at the bottom right corner of the tweet
No. They changed it. As before you could have two versions to 'tweet' with a short 140 characters and a long version. It was then for some mad reason restricted to 140 which is not clever if you want to have a bit of a long 'tweet' and makes what you can 'tweet' shorter as the address is counted as part of the letter count.
I don't think so.
Retweet/RetweetingRT stands for "ReTweet." To retweet someone's tweet/message is to share their tweet with your own Twitter followers. When you come across an interesting tweet and you want to help it spread - you retweet it.There's usually a ReTweet button next to each Tweet, so you can usually just click that.The syntax of a ReTweet is the abbreviation "RT" or the word "Retweet" followed by the username of the person who tweeted it (e.g @User) and then the content of the actual tweet.You may also modify the original tweet to make it more interesting for your followers, or because the addition of RT + username makes it longer than the permitted 140 characters. In order to make everything fit, you may need to omit words or use shorter synonyms or abbreviations.
A tweet is the sound some small birds make, like a budgie. A tweet is the name of a message sent from the Twitter system.
Tweet, re-tweet, Follow Friday are all examples of terminology found on Twitter.
Tweet, whistle, chirp, some birds even make other noises like Mockingbirds.
Many people use twitter, including me. To be honest, I use twitter to stalk celebrities, and yes some do reply to you. It's like the lottery, it will happen. Tweeting something new is easy, you just tweet whatever comes to mind. Overall, I don't really get your question, so hope that helped.
She does have a Facebook & a Twitter; you can tweet her @snooki. She does reply to some of her followers, so give it a try!