When tumblr was bought by one ridiculous corporation for a huge sum of money and immediately resold for peanuts, the remaining users there cheered in amusement. Look how much money we cost these corporations by just being useless freaks! That contributed in part, I think, to this idea: Everybody delete their twitter on the same day and tank the stock.
There are reasonable reasons for people to not participate, but for a lot of you I know twitter is nothing but an unhealthy tax on your minds and you could use an excuse or motive to excise it from your life. Why not make it a form of direct action and kick Apartheid Jr right in his spaceballs? Delete your Twitter at the appointed hour. Huzzah!