On the morning of September 28 Research In Motion's (RIM) "BlackBerry PlayBook" touchscreen tablet is the most hotly discussed subject on Twitter.

"Blackberry playbook looks awesome!! And will be much better than ipad for sure,"
"will not be purchasing a Blackberry Playbook, principally because of its ridiculous name" and "Liking the new Blackberry PlayBook, smart move for RIM playing on their strengths and going after the corp market first" tweet microbloggers about RIM's just-announced tablet.

A hoax tweet by Twitter user @Quakeprediction warning people of a major earthquake set to take place in the US has sent microbloggers living in Southern California on an "Earthquake Warning" tweeting spree.

The term has made it into second place on the charts as some users retweet the warning and others point out that tweets are a hoax as earthquakes cannot be predicted.

"#iwannaknowwhy" is unchanged in third place, "#newtwitter" moves back into the charts in fourth place, and "#oneofmyfavoritemovies" drops three places to number five.

The name of personal two-wheel transporter maker "Segway" has hit sixth place in the charts. Jimi Heselden, owner of the company, died on September 26 after falling from his cross-country two-wheel electric transporter.

The name of American documentary TV series " Hoarders" is in seventh place, followed by the name of MTV reality documentary, The Buried Life ("Buried").

The Dutch word for "good morning" ("Goedemorgen") makes its way back into the charts in ninth place, while "Education" is today's promoted topic in tenth place.

The top 10 most talked about topics on Twitter on September 28 at 7:30 AM GMT are:

  1. BlackBerry PlayBook (new)
  2. Earthquake Warning (new)
  3. #iwannaknowwhy (unchanged)
  4. #newtwitter (re-entry)
  5. #oneofmyfavoritemovies (-3)
  6. Segway (new)
  7. Hoarders (new)
  8. Buried (new)
  9. Goedemorgen (re-entry)
  10. Education (promoted)