When lots of people are tweeting about the same thing then its became trend in the trending section of twitter.com.
twitter is the micro blogging platform where you can express anything in just 140-character.
so that your word should be very compact and clear within 140-character.
that’s why some people like twitter because viewer can easily right 140-character tweet.
also when lots of people writing about the same thing then twitter show most uses keyword as a trend on the trending section of the twitter.
most of the user try to use # before any trending keyword that’s why its called hashtags or what is the hashtags is trending on twitter.
trendguru,online is the best website for checking what is trending worldwide.
not only that if you want to check what is trending on twitter india then you can also find in trendguru.online.
in simple word when lots of people’s are writing same keyword in twitter its became trend.