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Lesson15HowDoSearchEnginesWork?
(第十五课搜索引擎如何工作?)
Vocabulary(词汇)ImportantSentences(重点句)Multiple-choiceQuestion(多选题)
Problems(问题)
Oneofthebiggestreasonswhymanyorganizationsarenotdoingevensimplethingstohelppeoplefindtheirwebsitesinsearchenginesistheysimplydon’tunderstandhowsearchengineswork.Thisarticleisintendedtoexplainthebasicsofhowsearchenginesworkandinthecourseofdoingsoshattersomesearchenginemythsandhelpyouunderstandwhatyoucandotohelppeoplefindyourwebsiteinsearchengines.1WhatisaSearchEngine?
Thefirsttosteptounderstandinghowsearchenginesworkistounderstandwhatasearchengineis.Thesimplestexplanationisthatsearchengineisatoolforfindingthingsonline.Therearemanydifferenttypesofsearchenginesbuttheycanbeputintotwomajorcategories.
1.1Human-PoweredDirectories
Thefirst“searchengines”werenotactuallysearchenginesaswethinkofthemtoday,butsearchabledirectoriesofwebsitesorganizedbyhierarchicalcategories.Asiteisaddedtoadirectorywhenthewebsiteownerfillsoutasubmissionformonthedirectory’swebsiterequestingtheirsitebeincludedinthedirectoryandincludetheirwebsite’stitle,description,URL(webaddress),andcategory.Amoderatorlaterreviewsthesiteandifitmeetsthedirectory’scriteriaalistingforthatsiteisaddedoractivated.TheoriginalYahoowasoriginallyahuman-powereddirectory,anddirectorieslikeOpenDirectoryProjectcontinueontoday.
Thedownsideofthehuman-poweredsearchengineisthatitonlyincludeswebsitesthathavebeensubmittedtoit,whichmeansyoumaynotfindwhatyou’relookingforespeciallyifit’sanewwebpage.[1]Theotherdownsidefromthedirectories’pointofviewisthatreviewingeverysitesubmittedisverylabor-intensiveandcostly.Iknowbecausemycompany’s“searchengine”,OurChurch.Com’sDirectoryofChristianWebsites,likealmostallchurch/Christian“searchengines”,isahuman-powereddirectory.
1.2Crawler/Spider-PoweredSearchEngines
Thenextgenerationofsearchengineshasprogramswhichactivelyseekoutnewsitesandreadthemintotheirindexes.Theseprogramsarecalledcrawlers,spiders,robots,orbots.Alloflargestandmostpopularsearchenginestodayareofthistype,includingGoogle,Yahoo,MSN,andAsk.Therestofthisarticleisfocusedonhowthesecrawler/spider-poweredsearchenginesworkbecausemorethan99%ofsearchesaredoneonthistypeofsearchengine.2TheCrawler
(1) Searchbotsperiodicallyrereadeverywebpageintheirdatabase.Whydoesthismatter?
Youdon’thavetodoanythingwhenyouchangeyoursite.Ifyoursiteisalreadylistedinasearchengineandyoumakechangestoyourwebsite,searchengineswilleventuallyupdatetheirinformation.
Youdohavetobepatient.Thefrequencyofre-crawlingvariesdependingonthesearchengine,theimportanceofyoursite(asdeterminedbythesearchengines),andhowoftenyouupdateit.Itcouldtakeadayoritcouldtakemorethanaweek.
(2) Searchbotsfollowlinksonthepagesthathavealreadybeencrawledinordertofindnewpages.Whydoesthismatter?
Ifyouaddanewpagetoyourwebsiteorcreateanewwebsite,it’simportanttoaddalinktoitonawebpagethatisalreadyinthesearchengines.
Ifawebpagethatisalreadyinthesearchengineshasalinktoyournewpageornewwebsite,youdonotneedtosubmitarequesttothesearchenginestocrawlthenewpageorwebsite,thoughitmaystillbeworthdoingjusttobesureyourwebsitewillbefoundquickly.
(3) Somesearchengineshaveformsyoucansubmittorequestawebsitebecrawled.Whydoesthismatter?
Ifyouhaveanewwebsiteandnositeslinktoit,searchbotswillnotbeabletofindit.Inthiscase,submittingaformtothesearchenginerequestingyoursitebelistedorindexedcangetitintosearchengines.
Becausehuman-powereddirectoriesdonothavesearchbots/crawlers,tobelistedinthemyoumustsubmitarequestform.[2]
2.1TheRankingAlgorithm
Sometimeafterawebpagehasbeencrawledbythesearchbotorcrawler,thesearchenginethenprocessesorindexesthepagetodeterminewhatsearchwordsandphrasesthepageisrelevanttoaswellashowrelevantthatpageiscomparedwithotherwebpagesforthosephrases.Duringthisprocessingthesearchenginelooksatmanydifferentfactorsincludinghowmanytimeseachwordandphraseoccursonthepage,whichwordsareinheadingsorbold,thedomainnameofthesite,filenameofthepage,thepagesthatlinktothepage,andmanymore.
Exactlywhichfactorsasearchenginelooksatandhowthey’reweightediscalledthesearchengine’ssearchrankingalgorithm.[3]It’slikethesearchengine’s“secretsauce.”Eachsearchengine’salgorithmisdifferentandeachisaheavilyguardedsecret.
Whydoesthismatter?
Thereistimebetweenwhenyoursiteiscrawled(orrecrawled)andwhenitisprocessedorindexed.So,itcantakeaslittleasafewhourstomanydaysorweeksbeforechangestoyourwebsitemayproducechangesinitssearchrankings.
Becauseeachsearchengine’srankingalgorithmisdifferent,awebpagecanbe#1inGooglebut#20inYahooforaparticularphrase.
Becauseeachsearchalgorithmisaheavilyguardedsecretnobodyoutsideofafewselectengineersateachsearchengineknowsexactlyhowmucheachparticularfactorweighsintotherankingsofeachsearchengine.But,peoplewhospendtheirprofessionalliveshelpingsitesrankbetterinsearchengineshavegainedverygoodideaastowhatfactorsmattermost.
Becausethesearchrankingalgorithmslookattext,headings,andotherelementsonawebpage,changingthingsonthewebpagecanchangewherethatwebpageappearsinthesearchresults.
Searchrankingalgorithmslookatfactorsoutsideofawebpage,suchastheageofawebsiteandlinkstothewebpage.So,thereareotherfactorswhichyoumayhavelessinfluenceover.
Thegoalofeverysearchengineistodisplaytotheusertheinformationorwebsitestheuserislookingfor.Inotherwordseverysearchenginewantstoprovidethebest,mostrelevantresults.Asaresult,searchenginesareconstantlyimprovingtheiralgorithmsandincludingnewfactorswhichtheythinkwillproducebettersearchresults.[4]Whydoesthismatter?Assearchalgorithmschange,sowillyourwebsite’ssearchenginerankings.
2.2TheSearchEngineResultsPages(SERPs)
Thecrawlingofwebsitesandindexingofwebpagesareconstantlygoingonevenwhennooneissearching.Thelastpartinthesearchprocessispartthatyou’reprobablymostfamiliarwith–theactualsearch.Youtypeinaword,shortphrase,orquestion,andthesearchenginedisplaysalistofwebsites.ThatlistofwebsitesiscalledthesearchengineresultspageandsometimesreferredtoastheSERPs.IfyoudoasearchandlookattheSERP,you’llnoticetwocolumns.Abovetherightcolumnitsays“SponsoredLinks”.Thesearepaidadvertisements.ThecompaniesandorganizationslistedherepayafeetoGoogleforeachpersonwhoclickstheirad,sothey’reoftenreferredtoasPay-Per-ClickorPPCads.Intheleftcolumnaretheunpaidsearchresultsalsosometimescalledtheorganicresultsornaturalresults.Thesearethewebsitesthesearchenginebelievesaremostrelevanttothesearchphrasethatwasqueried.Sometimessearchenginesalsodisplaysponsoredlinksintheleftcolumnabovethenaturalresultsorwillevenplaceablockofpay-per-clickadsinthemiddleofthenaturalresults.Sponsoredlinksarealwayslabeled,thoughnotalwaysveryclearly.3WhydoesthisMatter?
Fromthesearcher’sperspective,thereisnothingwrongwithclickingonapaidlink.Youmayfindwhatyou’relookingforthere.Butit’simportanttobeawareofwhichwebsitespaidtobeintheresultsandwhicharetherenaturally.
Fromthewebadministrator’sperspective,it’simportanttounderstandtherearetwoopportunitiestogettothetopofthesearchenginerankings,throughnaturalresultsandbypurchasingpay-per-clickadvertising.4HelptheSearchEngines
Withabetterunderstandinghowsearchengineswork,youcanmakebetterdecisionsaboutthemarketingofyourwebsitethoughsearchengines.Searchenginesneedyourhelptofindyourwebsiteandtoknowwhatwordsandphrasesit’srelevantfor.Givethemthehelptheyneed.That’swheresearchengineoptimizationcomesin,butI’llgettothatonanotherday.1. enginen.发动机,引擎。
2. hierarchicaladj.分等级的。
3. downsideadj.下降趋势的。
4. algorithmn.运算法则。
5. botn.robot的缩写。Vocabulary
[1]Thedownsideofthehuman-poweredsearchengineisthatitonlyincludeswebsitesthathavebeensubmittedtoit,whichmeansyoumaynotfindwhatyou’relookingforespeciallyifit’sanewwebpage.
人力搜索引擎的崩溃在于它只包含已经被提交的网站,这意味着你不可能查询到你想要的东西,尤其是在搜索新网页的情况下。句中的第一个that引导表语从句,第二个that引导的从句作为定语从句修饰websites。关系代词which在从句中作主语。ImportantSentences
[2]Becausehuman-powereddirectoriesdonothavesearchbots/crawlers,tobelistedinthemyoumustsubmitarequestform.
因为人力文件夹没有被列出的搜索机器人(爬行者),因此你必须提交一个请求表格。句中because引导原因状语从句,tobelistedinthem作为定语修饰bots/crawlers。
[3]Exactlywhichfactorsasearchenginelooksatandhowthey’reweightediscalledthesearchengine’ssearchrankingalgorithm.
实际上搜索引擎关注哪些因素以及这些因素的比重被称为搜索引擎的搜索等级算法。句中which和how引导的从句是两个并列的主语从句。
[4]Asaresult,searchenginesareconstantlyimprovingtheiralgorithmsandincludingnewfactorswhichtheythinkwillproducebettersearchresults.
结果,搜索引擎一直在改善它们的算法并且包含它们所能想到的新的因素,这一切将产生更好的搜索结果。句中whichtheythink作为定语从句修饰factors,整个句子的主语由一个主语从句来表示。
(1) Accordingtothearticle,whataremajorcategoriesofsearchengi
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