Is there a science to getting retweets? Viral marketing scientist Dan Zarella has studied retweets and his nine rules for getting them, as reported on the Fast Company blog.

1. Whatever you do, don't use tinyurl. That's the least likely to get retweeted. Go for bit.ly, ow.ly, su.pr and is.gd instead.

2. Use the most retweetable words and phrases like you, twitter, please, retweet, blog, post, free, media, help, how to and 10.

3.Don't use boring words like going, watching, listening, night, bed, gonna, hey and tomorrow.

4.Don't be afraid of being intellectual and challenging. Conversely, don't be stupid.

5.Use punctuation. According to Zarella, 98% of RTs have some form of punctuation (compared with 86% of normal tweets). Colons, periods, exclamation points, commas, and hyphens rate well. Semi colons don't.

6. Breaking news stories get more retweets.

7. Nouns, proper nouns and third person verbs are heavily retweeted. For example, Britney Spears gets hitched (again)

8.Don't use Twitter to vent your emotions. It's fine to tweet about work, money and media but no one really wants to know how angry or depressed you are, and swearing at the world is a turn off.

9. Pick your times for tweeting carefully. Zarella recommends 4pm on a Friday.