CS6322: CS6322: Information Retrieval Information Retrieval Sanda HarabagiuSanda HarabagiuLecture 10: Web search basicsLecture 10: Web search basicsCS6322: Information RetrievalCS6322: Information RetrievalBrief (non-technical) history Early keyword-based engines ca. 1995-1997 Altavista, Excite, Infoseek, Inktomi, Lycos Paid search ranking: Goto (morphed into Overture.com → Yahoo!) Your search ranking depended on how much you paid Auction for keywords: casino was expensive!CS6322: Information RetrievalCS6322: Information RetrievalBrief (non-technical) history 1998+: Link-based ranking pioneered by Google Blew away all early engines save Inktomi Great user experience in search of a business model Meanwhile Goto/Overture’s annual revenues were nearing $1 billion Result: Google added paid search “ads” to the side, independent of search results Yahoo followed suit, acquiring Overture (for paid placement) and Inktomi (for search) 2005+: Google gains search share, dominating in Europe and very strong in North America 2009: Yahoo! and Microsoft propose combined paid search offeringCS6322: Information RetrievalCS6322: Information RetrievalAlgorithmic results.PaidSearch AdsCS6322: Information RetrievalCS6322: Information RetrievalWeb search basicsThe WebAd indexesWeb Results 1 - 10 of about 7,310,000 for miele. (0.12 seconds) Miele, Inc -- Anything else is a compromise At the heart of your home, Appliances by Miele. ... USA. to miele.com. Residential Appliances. Vacuum Cleaners. Dishwashers. Cooking Appliances. Steam Oven. Coffee System ... www.miele.com/ - 20k - Cached - Similar pages Miele Welcome to Miele, the home of the very best appliances and kitchens in the world. www.miele.co.uk/ - 3k - Cached - Similar pages Miele - Deutscher Hersteller von Einbaugeräten, Hausgeräten ... - [ Translate this page ] Das Portal zum Thema Essen & Geniessen online unter www.zu-tisch.de. Miele weltweit ...ein Leben lang. ... Wählen Sie die Miele Vertretung Ihres Landes. www.miele.de/ - 10k - Cached - Similar pages Herzlich willkommen bei Miele Österreich - [ Translate this page ] Herzlich willkommen bei Miele Österreich Wenn Sie nicht automatisch weitergeleitet werden, klicken Sie bitte hier! HAUSHALTSGERÄTE ... www.miele.at/ - 3k - Cached - Similar pages Sponsored Links CG Appliance Express Discount Appliances (650) 756-3931 Same Day Certified Installation www.cgappliance.com San Francisco-Oakland-San Jose, CA Miele Vacuum Cleaners Miele Vacuums- Complete Selection Free Shipping! www.vacuums.com Miele Vacuum Cleaners Miele-Free Air shipping! All models. Helpful advice. www.best-vacuum.com Web spiderIndexerIndexesSearchUserSec. 19.4.1CS6322: Information RetrievalCS6322: Information RetrievalUser Needs Need [Brod02, RL04] Informational – want to learn about something (~40% / 65%) Navigational – want to go to that page (~25% / 15%) Transactional – want to do something (web-mediated) (~35% / 20%) Access a service Downloads Shop Gray areas Find a good hub Exploratory search “see what’s there”Low hemoglobinUnited AirlinesSeattle weatherMars surface imagesCanon S410Car rental BrasilSec. 19.4.1CS6322: Information RetrievalCS6322: Information RetrievalHow far do people look for results?(Source: iprospect.com WhitePaper_2006_SearchEngineUserBehavior.pdf)CS6322: Information RetrievalCS6322: Information RetrievalUsers’ empirical evaluation of results Quality of pages varies widely Relevance is not enough Other desirable qualities (non IR!!) Content: Trustworthy, diverse, non-duplicated, well maintained Web readability: display correctly & fast No annoyances: pop-ups, etc Precision vs. recall On the web, recall seldom matters What matters Precision at 1? Precision above the fold? Comprehensiveness – must be able to deal with obscure queries Recall matters when the number of matches is very small User perceptions may be unscientific, but are significant over a large aggregateCS6322: Information RetrievalCS6322: Information RetrievalUsers’ empirical evaluation of engines Relevance and validity of results UI – Simple, no clutter, error tolerant Trust – Results are objective Coverage of topics for polysemic queries Pre/Post process tools provided Mitigate user errors (auto spell check, search assist,…) Explicit: Search within results, more like this, refine ... Anticipative: related searches Deal with idiosyncrasies Web specific vocabulary Impact on stemming, spell-check, etc Web addresses typed in the search box “The first, the last, the best and the worst …”CS6322: Information RetrievalCS6322: Information RetrievalThe Web document collection No design/co-ordination Distributed content creation, linking, democratization of publishing Content includes truth, lies, obsolete information, contradictions … Unstructured (text, html, …), semi-structured (XML, annotated photos), structured (Databases)… Scale much larger than previous text collections … but corporate records are catching up Growth – slowed down from initial “volume doubling every few months” but still expanding Content can be dynamically generatedThe WebSec. 19.2CS6322: Information RetrievalCS6322: Information RetrievalSpam (Search Engine Optimization)CS6322: Information RetrievalCS6322: Information RetrievalThe trouble with paid search ads … It costs money. What’s the alternative? Search Engine Optimization: “Tuning” your web page to rank highly in the algorithmic search results for select keywords Alternative to paying for placement Thus, intrinsically a marketing function Performed by companies, webmasters and consultants (“Search engine optimizers”) for their clients Some perfectly legitimate, some very shadySec. 19.2.2CS6322: Information RetrievalCS6322: Information RetrievalSearch engine optimization (Spam) Motives Commercial, political, religious, lobbies Promotion funded by advertising budget Operators Contractors (Search Engine Optimizers) for lobbies, companies Web masters Hosting services Forums E.g., Web master world ( www.webmasterworld.com ) Search engine specific tricks Discussions about academic papers ☺Sec. 19.2.2CS6322: Information RetrievalCS6322: Information RetrievalSimplest forms First
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