While Twitter has grown increasingly mainstream since the middle of last year, April 2009 could be the month that really put the company on the map. That’s when Ashton Kutcher raced CNN to be the first with 1 million followers; that’s when Oprah joined; and that’s when traffic exploded by more than 7 million new U.S. visitors.
comScore says the service attracted 17.0 million U.S. unique visitors in April, up 83% from March and more than four times the 4.0 million unique visitors it attracted in February. The “hockey stick” growth curve in the chart below is rare and incredible.
Standard disclaimer: These stats just show how many people visited Twitter’s Web site — it’s not an apples-to-apples measurement of subscriber growth, doesn’t reflect mobile usage, desktop apps, etc.
And as comScore’s weekly data shows, the company could show slower growth in May, as traffic slows post-Oprah. We’ll have a better big-picture idea of Twitter’s continued mainstream adoption in a few months.