Twitter has revealed the hottest hashtags for the year 2011, which include both serious topics as well as some fads that caught the attention of the cyber populace of the world.

#egypt was the top hashtag of this year, followed by #tigerblood, #threewordstoliveby and #idontunderstandwhy. #japan was at the fifth position as tsunami and earthquake hit the Asian island country in March.

On the technology front, Apple’s Mac App Store was the most popular subject on the social network, followed by the Sony NGP (now known as the PlayStation Vita), Guitar Hero, and Mozilla Firefox. Duke Nukem Forever took the fifth spot.

In world news, Hosni Mubarak’s resignation was the top topic, followed by Osama bin Laden’s shooting down in Pakistan.

Twitter wrote in a blog post said that the list of Hot Topics and Top Hashtags charts the keywords that rose the fastest in conversation over the course of the year. "This reveals what grabbed our attention most dramatically in 2011, and which events, inventions, changes, and ideas made the deepest impression on us," the company said.