users to receive interesting tweets and avoid spam, despite the site using the broadcast model, in which all tweets from a user are broadcast to all followers of the user. Spammers, out of malicious intent, post either unwanted (or irrelevant) information or spread misinformation on social media platforms. Social spam Spreading beyond the centrally managed social networking platforms, user-generated content increasingly appears on business, government, and nonprofit websites worldwide. Fake accounts and comments planted by computers programmed to issue social spam can infiltrate these websites. Blog, wiki, and guestbook Blog spam is spamming on weblogs. In 2003, this type of spam took advantage of the open nature of comments in the blogging software Movable Type by repeatedly placing comments to various blog posts that provided nothing more than a link to the spammer's commercial web site. Similar attacks are often performed against wikis and guestbooks, both of which accept user contributions. Another possible form of spam in blogs is the spamming of a certain tag on websites such as Tumblr. Spam targeting video sharing sites In actual video spam, the uploaded video is given a name and description with a popular figure or event that is likely to draw attention, or within the video a certain image is timed to come up as the video's thumbnail image to mislead the viewer, such as a still image from a feature film, purporting to be a part-by-part piece of a movie being pirated, e.g. Big Buck Bunny Full Movie Online - Part 1/10 HD, a link to a supposed keygen, trainer, ISO file for a video game, or something similar. The actual content of the video ends up being totally unrelated, a Rickroll, offensive, or simply on-screen text of a link to the site being promoted. In some cases, the link in question may lead to an online survey site, a password-protected archive file with instructions leading to the aforementioned survey (though the survey, and the archive file itself, is worthless and doesn't contain the file in question at all), or in extreme cases, malware. Others may upload videos presented in an infomercial-like format selling their product which feature actors and paid testimonials, though the promoted product or service is of dubious quality and would likely not pass the scrutiny of a standards and practices department at a television station or cable network. VoIP Spam VoIP spam is VoIP (Voice over Internet