Twitter revealed this stat, along with several others, Thursday. Of those 100 million active users, approximately half sign on every day. And 40 percent of all active users don't even tweet, choosing instead to soak up what other people are saying. Also, did you know that two thirds of NBA players are on Twitter?

Despite a healthy base of regular users--and plenty of notable celebrities--Twitter's not perfect, nor is its work finished. Here's what Twitter needs if it wants to nab another 100 million users.

Solve the "I Don't Tweet" Problem

The fact that 40 percent of Twitter's active users stay silent isn't a bad thing, but people who don't use Twitter might not know this. I often hear people dismiss the service off hand because they don't have anything to say. Twitter needs to convince these people that there's still a lot of value in soaking up tweets from other users.

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