• by Erik Sass , Staff Writer @eriksass1, July 11, 2016

Publishers who were pinning their hopes for audience growth on Facebook should be very, very worried, judging by new data from online market intelligence firm SimilarWeb, which shows a precipitous drop in traffic for almost half the publishers on the social network. Furthermore, SimilarWeb points out that the decline in traffic came before Facebook announced changes to its algorithm that will reduce the amount of publisher content in users’ news feeds, suggesting worse is to come.

Overall, 139 out of the 300 biggest publishers on Facebook have seen their traffic decline year over year, including big names like Buzzfeed, Huffington Post, Bleacher Report and Elite Daily, SimilarWeb reports. For example Buzzfeed’s Facebook referral traffic fell 11.5% from 227.6 million in the first quarter of 2015 to 201.3 million in the first quarter of 2016. Meanwhile Huffington Post’s Facebook referral traffic plunged 44% to 84.9 million in the first quarter, the New York Times was down 10% to 68.5 million, and Mashable fell 17% to 51.8 million.

Further down the totem pole MSN.com declined 45% to 33.6 million, Time.com fell 33% to 27 million, and ESPN.go.com slid 46% to 31.2 million.

However, SimilarWeb was quick to note that it wasn’t bad news across the board, as some publishers actually enjoyed big increases. Notable examples in this column included Littlethings.com, up 16% to 87.7 million; Vice, up 31% to 75.7 million; and CNN.com, up 14% to 52.5 million.

As noted, Facebook recently revealed that it is tweaking the algorithm governing which content shows up in user’s newsfeeds, reducing the amount of content from publishers in favor of more content from their Facebook friends. The new system prioritizes personal content over news and information, which in turn, takes precedence over entertainment content, as set forth in Facebook’s summary of the “values” determining which types of content get the most exposure. It covers all types of content from publishers, including article links, video, and live video.

The SimilarWeb data confirms trends identified by other analytics firms. Last month, data from SocialFlow showed that the average reach for a story posted on Facebook plunged from 117,000 in January to just 68,000 in May.

Separately, another study from analytics firm SocialWhip found that the combined activity for the ten biggest English-language publishers on Facebook fell from 287 million engagements per month in July 2015 to 162 million per month in April of this year, for a 44% decline over this period.