If you are reading this article you might want to check these links to catch up on what I'm proposing (CNet Article, Mashable, AppScout), 4chan is a suspect behind a Twitter "attack" and might be part of the reason that regular user accounts have been banned by accident by human error.

Solution....

Pay a one time joining fee of $2 or something very small to "join twitter". This will cut down on spam and it's not enough to stop people from wanting to be apart of Twitter. Have a free use account that anyone can sign up for and tweet with, but your information isn't able to trend and hash information doesn't work unless you are a "Verified Tweeter" or pay the something small initial use and getting used to the full functionality of Twitter. This would cut down on bad topics but wouldn't stop people from adding newbies as friends or allowing them to view this information but just not allowing them to contribute to the searchable information.

It's also known that Twitter is working on a system in beta to Verify Accounts but the information from that isn't available to the public how this is rolling out and if it's only going to be for people who are of a more famous variety, like Tony LaRussa (Story 1 and Story 2)

The burden shouldn't need to be placed upon the users, but this would be a very easy way to get the honest users of this great web 2.0 tool and keep the abusers away with the slight fee. Twitter would be able to look quickly and tell if a user is a "Verified Tweeter" or if they are a new user that just signed up. This would also slow the bot following traffic that people get when a spammer follows them and has nothing but spamming links on their account.

I'm a broke guy and who lives in a college town, but I know that people who like Twitter and hate this gaming the system and spamming would love to get this stuff under control and wouldn't have a problem paying a one time, very small fee to "Verify" their account.