GoogleÂ Inc.Â began shuffling its rankings for mobile websites Tuesday, potentially benefiting sites like job board Indeed.com and real-estate companyZillow GroupÂ Inc.,Â and hurting others like retailerÂ ZumiezÂ Inc.Â and IRS.gov.
Google said it tweaked its algorithm for mobile searches to favor sites that look good on smartphone screens, and penalize sites with content that is too wide for a phone screen and text and links that are too small.
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Given Googleâs importance in driving traffic to websites, some in the industry dubbed the change âmobilegeddon.â Google updates its algorithm frequently, but this is considered by some experts to be its most significant change in years. In an unprecedented move, Google warned website operators in February that the change was coming, and gave them tips on how to prepare.
âA lot of sites have been racing to beat the clock on this issue,â said Mark Ballard, director of research at Merkle RKG, a search-marketing firm.
The change is also important for Google. A company executive said at a conference last year that searches from mobile devices were poised to surpass searches on personal computers.
But advertisers typically pay less for clicks from phones, because they donât lead to sales as often. Encouraging developers to tailor sites to look good on smartphones should lead to more sales and consequently higher prices for Googleâs mobile ads, saidÂ Matt Ackley,Â chief marketing officer of Marin Software, an advertising technology firm. Advertising accounted for 90% of Googleâs $66 billion in revenue in 2014.
Google also wants more users to surf the Web on their phones instead of using mobile apps. Google sells ads that point to websites, but generally cannot direct searches to content inside apps. Some companies, including India e-commerce giant Flipkart, have dumped their mobile websites and told visitors to use their mobile apps instead.
âAs people increasingly search on their mobile devices, we want to make sure they can find content thatâs not only relevant and timely, but also easy to read and interact with on smaller mobile screens,â a Google spokeswoman said.
In a blog post Tuesday, Google said it had seen a 5 percentage point increase in the proportion of sites that are âmobile friendlyâ since its February announcement. The spokeswoman declined to specify the percentage of sites that are mobile friendly.
The change isnât simple for sites to roll out, since they must change all of their websiteâs pages to optimize them for smartphone screens.
According to a Google testing tool, the websites of Zumiez, technology wholesalerÂ CDWÂ Corp.Â and the IRS arenât mobile friendly. Nor is Googleâs own Finance site for stock quotes and related information.
United Healthcare Services Inc.âs primary site also failed Googleâs test for mobile friendliness. However, the company has an additional site for people it insures that a spokeswoman said is designed for smartphones.
Zumiez, CDW and the IRS didnât respond to requests for comment. Google didnât respond to a request for comment on its Finance site.
Failing the test doesnât mean sites will automatically fall out of Googleâs rankings on smartphones, notes Rand Fishkin, founder of Moz, which makes software to help site operators improve their search rankings. Mobile-friendliness is just one of over 200 different âsignalsâ that Google uses for ranking its results, the company said.
Research firm Searchmetrics said Zillow and Indeed saw a boost in their search rankings recently. Searchmetrics said Google may have started testing its new algorithm before Tuesday.
Jeremy Wacksman, vice president of marketing and product management at Zillow, said the real-estate information site has long designed new features with mobile devices primarily in mind, because roughly 70% of its traffic comes from mobile devices. Indeed didnât return requests for comment.
The governmentâs preparedness for Googleâs change varies. While the IRS website fails GoogleâsÂ test for âmobile friendliness,âÂ FEMA.gov and Healthcare.gov get passing grades.
Winners and losers from the change wonât be fully clear until after Google finishes rolling out the new update, which it said will happen over the next week.