IS2140_Reading notes_Unit 10

1, Power law:

In power law, the total number of web pages with in-degree i is proportional to1/iα. The value of αtypically reported by studies is 2.1.

2, Spam

First generation of spam in the context of web search is the manipulation of web page content for the purpose of appearing high up in search results for selected keywords. To avoid irritating users with these repetitions, sophisticated spammers restored to such tricks as rendering these repeated terms in the same color as the background.  More complex spamming techniques involve manipulation of the metadata related to a page including the links into a web page.

3, Search Engine Optimizers

SEOs provide consultancy services for clients who seek to have their web pages rank highly on selected keywords.

4, Cost Per Mil(CPM) basis: the cost to the company of having its banner advertisement displayed 1000 times. An advertisement (1) is priced by the number of times it is displayed (impressions); (2)is priced by the number of times it was clicked on by the user(cost per click model).

5, Several aspects of Goto’s model are worth highlighting.

(1) A user typing the query q into Goto’s search interface was actively expressing an interest and intent related to the query q.

(2) Goto only got compensated when a user actually expressed interest in an advertisement – as evinced by the user clicking the advertisement.

 6, Search Engine Marketing (SEM):

For advertisers, understanding how search engines do this ranking and how to allocate marketing campaign budgets to different keywords and to different sponsored search engines has become a profession known as search engine marketing (SEM).

 7, How do search engines differentiate themselves and grow their traffic? Google identified two principles that helped it grow at the expense of its competitors:

(1) a focus on relevance, specifically precision rather than recall in the first few results;

(2) a user experience that is lightweight, meaning that both the search query page and the search results page are uncluttered and almost entirely textual, with very few graphical elements.

 8,  Three categories of web search queries:

(1) Informational queries seek general information on a broad topic

(2)Navigational queries seek the website or home page of a single entity that the user has in mind, say Lufthansa airlines.

(3)A transactional query is one that is a prelude to the user performing a transaction on the Web – such as purchasing a product, downloading a file or making a reservation.

9， Teleport operation：

 In the teleport operation the surfer jumps from a node to any other node in the web graph.

10,A Markov chain is a discrete-time stochastic process: a process that occurs in a series of time-steps in each of which a random choice is made. A Markov chain consists of N states. Each web page will correspond to a state in the Markov chain we will formulate.