In a recent post terraroisin discussed Google’s AdWords Learning Center, which is a lessons catalog for anyone with questions about the AdWords program. The learning center provides detailed information on many of the concepts we saw in class (e.g., Cost-per-click (CPC) and Clickthrough Rate (CTR)), and seems to be a great reference to supplement the material covered in class.

Also on the topic of information search, beefcake raised the question of whether it would be possible to design a system which can filter information from web pages. An interesting answer was provided by ahuckk. In class, we focused on the traditional query-based search engines. Some new social media sites, such as blogs, wikis, Digg and Flickr, rely on the users to actively create, evaluate and distribute information, thus providing an effective information filtering approach. For example, Digg allows users to submit, vote on, and discuss news stories they find on the web. The votes of users determine which stories are promoted to the front page. Interestingly, the voting system of Digg is also related to another topic we covered in class: information cascades. A study by Kristina Lerman shows that Digg users are more likely to be interested in the news stories their friends also find interesting, and the filtering may result in overrepresentation of an article.

Continuing with the topic of information cascades, a recent post by easy shows how information cascades can be easily demonstrated in the classroom setting. Another post by ltdtl used personal experience to illustrate two topics related to information cascades: the bandwagon effect and groupthink.

A number of posts focused on the role of information cascades in different settings. A post by lyts discussed the application of the information cascade theory to the upcoming 2008 presidential election. Since the primary system became a central role in 1972, states have been moving their primaries towards the front of the election calendar in an attempt to increase their influence. Both ithacaiscold and njr25 wrote posts about information cascades in the film industry. As introduced by ithacaiscold, the blockbuster strategy is based on the theory that audiences tend to choose movies with heavy advertising, big stars, and strong opening box office sales. A paper by De Vany and Walls argues that this non-informative cascade of the opening will turn into an informed cascade, and thus movie quality still matters. The movie-going audience cannot be manipulated and a movie will be a hit only if it initiates a positive word-of-mouth information cascade. A post by andykupe describes how scamsters use information cascades to profit from the lightly regulated Pink Sheets stock market. Since the stocks traded on the Pink Sheets usually have low volume, scamsters can easily manipulate drastic volume changes to start an information cascade and drive up the stock price. Scamsters then sell their shares at a profit, leaving other investors holding worthless stocks. This scheme is called “pump-and-dump”.