5 The most popular sites, according to Alexa, were Facebook, Twitter, Instagram, Snapchat, YouTube, LinkedIn, and Pinterest.
The least popular were Tumblr, Reddit, and Reddit.
Alexa found that only a minority of people used these sites to discuss politics or political topics.
It noted that, by far, the most popular social media platforms are Facebook, LinkedIn and Twitter.
(It is not possible to determine which social media site people actually use.)
Facebook, which is used by more than a billion people, reported a higher share of total visits to the site last year than Twitter, Google, or Google+.
The other two, Google and Twitter, had the largest share of visits to each other.
Pinterest had the second largest share last year, according the Alexa report.
The Alexa study did not look at the popularity of specific social media websites, such as Facebook, and its data does not include social media accounts for which people could not be identified.
Twitter did not provide data for social media pages and did not include a website in its top 10 most popular websites for 2016.
(The Twitter page for 2016 is no longer active, according Google.)
The Alexa research also found that, compared with 2015, the number of people who visit Facebook increased in 2016, as did the number who visited Twitter.
The average number of visits for each site increased by about 25% in 2016.
Twitter also reported that it saw a surge in the number it saw for Facebook and Instagram in the fourth quarter of 2016, up by about 30% compared with the same quarter a year earlier.
Twitter saw a spike in the share of visitors who visited a website for which it did not have direct access.
But, according it, this was a relatively small share compared with a share of visitor visits for which the website did have direct interaction with the visitor.
Alexa also found a surge for Twitter in visits to blogs and news sites, where it saw an increase in visits in 2016 compared with 2014.
(Twitter reported a 10% increase in total page views in 2016 over 2015, but not the number visited by each of the sites, which was similar to the number reported for blogs and other websites.)
Alexa also measured the number and types of Facebook ads that people saw, with an emphasis on the “click to like” and “like” buttons.
Facebook ads accounted for about 1% of visits in the first quarter of this year, while Twitter ads accounted at about 10%.
Google ads accounted in the second quarter of the year for about 6% of visitors to the websites.
Facebook and Twitter also had the highest percentage of visits of people on mobile devices, according a recent study.
Facebook had the lowest percentage of mobile visitors in 2016 with only 4% of its visitors coming from mobile devices.
(Google reported that mobile visitors made up about 9% of the total visit to its websites in 2016.)
Twitter had the best mobile conversion rate, at 18%.
Instagram, LinkedIn , Pinterest, Tumblr and Reddit had the worst mobile conversion rates, with about 10% of their mobile visits coming from their mobile apps.
Instagram had the most mobile visits, with more than 2 million mobile visits in all.