Tweet more, and embrace the weekends.

That’s according to Dan Zarrella, a social media researcher (with 33,000 followers himself). Zarrella works for HubSpot, mining data on hundreds of millions of tweets, blog posts, and email newsletters to help marketers find trends. News organizations should pay attention, too.

Zarrella says the right Twitter strategy depends in part on what your goals are. Want to accumulate as many followers as possible? Then tweet a lot: Twitter’s A-listers — those with the most followers — tweet an average of 22 times a day, and more tweets generally lead to more followers. But if your goal is to drive more traffic to your site, you should show a little more restraint; accounts that share two or more links an hour show a dramatically lower clickthrough rate than those who share no more than one.

It’s an inexact science, but at least it’s an attempt at science where so much social media strategy is driven by intuition. (Zarrella complains about the the “unicorns and rainbows” strategy: “Love your customers, hug your followers, engage in the conversations. It sounds like good advice, and it’s hard to disagree with,” he says. “But generally, it’s not based in anything substantial.”)

After collecting more than two years of data, Zarrella shared his findings Tuesday in a webinar called “The Science of Timing.” That science is less about when and more about when not — what he calls “contra-competitive timing.” The trick is to reach people when the noise of the crowd has died down.

It turns out that time is often the afternoons, when blogs and news sites are slower, and the weekend, when they’re all but asleep.

Retweet activity is highest late in the work day, between 2 and 5 p.m., and the sweet spot (tweet spot?) is 4 p.m., Zarrella’s analysis found. Late in the week is most retweetable, too. Zarrella created TweetWhen to tell Twitter users what time days and times yield the most retweets. (Our @niemanlab tweets get the most retweets around 9 p.m. and on Saturdays. Go figure. That’s our hour-by-hour chart up top.)

On weekend mornings, when most news sites see substantial drops in pageviews, Twitter clickthroughs spike, he says. Comment activity also jumps dramatically: Users have more time and attention to devote to content on the weekend, even if the content isn’t fresh, and fewer distractions compete for attention. On Facebook, Zarrella says, the effect is even more pronounced: Facebook participation on weekdays is infinitesimal in comparison. (He thinks it might be because so many companies block Facebook at the workplace.) Facebook does not reward frequent posting in the same way Twitter does, however, and it’s much easier to flood (and annoy) Facebook fans than Twitter followers. Postings on Facebook also tend to “stick around” longer, re-emerging when people post a comment or like.

Not only does Zarrella recommend tweeting more — he recommends tweeting the same links two or three times a day. Don’t bother calling it a “rerun” or apologizing to people who might have seen it before. Simply wait a few hours and change up the language. Only a fraction of your followers will see it the first time. Even an organization with thousands of followers won’t reach most of its audience most of the time. (As an experiment, social media star Guy Kawasaki once repeated the same tweet every day for nine days, and found the clickthrough rate remained high each time.)

Zarrella recently performed a similar deep dive into data for email newsletters, working with MailChimp to analyze 9.5 billion messages. A lot of the same lessons apply, he says: Email more, and embrace the weekends.

Most people who unsubscribe do so after receiving their first email. Send 30 emails a month or send five — it makes little difference, he found. (“Unsubscribers are doing you a favor,” he says — they don’t want to hear from you anyway.) The most important time to reach subscribers is right away, especially in the first couple of days after signup. The average click rate for the average user drops to almost nothing after four months. Like with blogs and social media, readers are more likely to open an email newsletter and click links on weekends. For all days of the week, early-morning hours (between 4 and 7 a.m.) are the best times to reach readers — before they get caught up in their to-do list for the day.

Here are the slides from Zarrella’s webinar: