What is Captology/Persuasive Technology ?
Captology is the study of computers as persuasive technologies including the design, research, and the analysis of interactive technologies intentionally created to change people's attitudes or behaviors. Captology includes two varieties of persuasion: "macrosuasion" and "microsuasion". Macrosuasion refers to products that are used exclusively for persuasion. Microsuasion refers to products that include components meant to persuade. (Cheng, 2003)
The word "Captology" is a partial acronym of Computers as Persuasive Technology and was first used in 1996 by Dr. BJ Fogg  of Stanford University. Dr. Fogg is a pioneer in the developing the field of Captology and runs the Persuasive Technology Lab  at Stanford.
Tagging on Facebook is available in photos, videos and status updates. Tagging is a very persuasive technique that Facebook uses in order to get users addicted. The way in which this works is that when someone is tagged to something, they become intrigued and go to see what someone has posted about them, or what they look like in a certain photo. This makes Facebook very 'persuasive'.
Tagging inspires interest in Facebook users to go on Facebook by sending the user an e-mail informing them that they’ve been tagged. In that e-mail is a link to whatever that person was tagged to. This is a simple one step action which does not require much effort on the user’s part. This brings the user into the Facebook system, giving the Facebook user ample opportunity to do other things on Facebook which allows the user to get addicted to Facebook easily. It is Facebook's goal to persuade as many people as possible to use Facebook.
“According to the Fogg's behaviour model, 3 things need to converge for behaviour change to occur: motivation, ability, and triggers...Put hot triggers in the path of motivated people”(Lily Cheng, Stanford University, 2010)
Hot triggers are a good example of captology, as they are very successful in getting people who come across them to change their behaviour. A hot trigger is a trigger that allows the user to follow through on the behaviour change instantly.
A very good example of hot triggers are links embedded in YouTube videos. These hot triggers allow the user to go to another video simply by clicking on the link, therefore there is high ability. Also the user is already watching a video by this user and therefore is highly motivated into watching similar content. Links embedded into YouTube videos are therefore very good at getting the user to do what the uploader of the video wants them to do - presumably watch more of their video content as opposed to someone else's videos.
We know that hot triggers work because a video “World Water Day Video from charity: water” raised $10,000 on the first day that the video was released on YouTube, by adding a donate link in the video.
Where is Captology used ?
Captology is used increasingly these days in a wide variety of technologies, including Web sites, PDAs, kiosks, mobile phones, and video games. The ability to use computers as persuasive technology has increased rapidly with the massive increase in Internet usage over the last decade.
An example of captology is companies that use automated instant messaging to send user alerts. Another example of captology is using computer technology inside products with the intention of influencing people a certain way. If a user interacts with a simulation program, it can be designed to encourage individuals to take a particular action. We also see examples of captology in the various wizards embedded into programs that attempt to encourage users to perform tasks a certain way.
Since the intent to persuade is a key aspect of captology, software programs, web sites, or other computer technology developed without such intent do not qualify as captology.
Interview with BJ Fogg: http://www.designcrux.netfirms.com/interview_fogg_captology.html
BJ Fogg talking about how tags on FaceBook persuade users: http://www.youtube.com/watch?v=RWTZYq1QaDg
BJ Fogg's blog: http://bjfogg.com/
Lily Cheng talking about YouTube links: http://www.youtube.com/watch?v=ZKZ2Lo9enlE&p=1104C5456D9CDB8D&feature=BF&index=12
B.J. Fogg Persuasive Technology: Using Computers to Change What We Think and Do