Lance Whitney, reporting for CNET:
Almost 9 percent of active Twitter user accounts don't necessarily have real users behind them. In a new filing with the Securities & Exchange Commission, the microblogging site revealed that in the three months ended June 30, around 8.5 percent of its active accounts used third-party apps that may have posted regular updates without any action on the part of an actual person. This means among the 271 million active Twitter accounts in total, around 23 million are bots, or automated accounts. I've lost count at how many times a spambot account replies to one of my tweets or follows me. It seems to me that a majority of my followers are spammers, and it's infuriating. Twitter really should be more vigilant in looking out for these types of accounts, and take steps to eradicate them.