Yesterday afternoon a large number of Twitter users began to notice that they were being added to a bunch of oddly named Twitter lists. Lists are normally used to group Twitter users by interest: "tech writers" or "top chefs." In this case, however, the lists had spammy names like GTA 5 Giveaway, Ashton Kutcher's Phone Number, and Candy Crush Saga Hack.

Unlike @ mentions, followers and direct messages, there is no way to block a user from adding you to a list, although you can still report that user for spam.

BuzzFeed tracked down a marketer, CelebPhoneNo, claiming to be behind the new method.

"I have been using this method for around two weeks now. You basically use a tool known as the 'Twitter Keyword Tool' which was only recently developed," the spammer told BuzzFeed. The tool scrapes keywords and uses a bot to add Twitter users to a list who have mentioned that term. A YouTube video explains in detail how the bot behind this technique works.

"I sense Twitter will quite obviously patch it soon," the spammer said. "This is the best at the moment and until it lasts I will continue to take advantage of it." We reached out to Twitter for comment, however the company is in the quiet period leading up to its IPO and is unlikely to respond.