There as many opinions about what's acceptable on Twitter as there are forums on Delphi. Ok, maybe more. :)
There have been thousands of articles written, most for the first time user, but every author has their own spin, and some are downright adamant that you must use Twitter in this way, or that way. Problem is, you're bound to run across someone that thinks that the way you're using it is wrong.
Bottom line? There is no right way or wrong way to use Twitter.
There's one pretty universal axiom though: Don't be creepy.
Another might be: Die, spammers, die.
No one likes the spammers that have invaded the public stream, but they don't bother you unless you're following a trend or a #hashtag conversation. You'll never see them in your normal Twitter use, because you have the power to follow, unfollow, or block people you find annoying.
I'll link to some of the many articles that have been written about Twitter etiquette in the next few posts.
Here's one article you can start with:
Chris Brogan's "Brief and Informal Twitter Etiquette Guide".
Chris Brogan is a blogger, social marketeer, and one of the "top Twitterers" (if there is such a thing.)
I like the alternate title he suggests... "You're Doing It Wrong." LOL