There’s no doubt that Twitter is a useful social media tool, extending well beyond the reach of traditional marketing strategies. Just how useful, with 140 million active users, and 340 million tweets per day, has been documented in an extensive report by Buddy Media issued this week.

In  the report titled “Strategies for Effective Tweeting: A Statistical Review” (PDF) Buddy Media analyzed user engagement on more than 320 handles on some of the most well-known brands. The results range from some no-brainers, to other less straightforward, but rather compelling insights, helping social marketers determine when, what, and how to tweet most effectively.

Here’s what they report came up with:

When: Tweeting during the “busy hours” between 7AM and 8PM yields 30% higher engagement rates than tweets that fall during “non-busy hours” of 8PM to 7AM. OK, nothing breakthrough there. Interestingly enough though, the trend on Facebook favors the contrary – the off-hours, which recieve 17% higher engagement rates during the “non-busy” time slot. Brands need not focus on just one day slot, as capitalizing on the peak times of both creates a constant conversation.

But over-zealous tweeters beware: posts should be limited to no more than four per day. Anything over that will activate the inverse relationship between tweet frequency and tweet engagement, so the more tweets per day, the less engaging they become.

What: It’s not just a matter of what you say, or how you say it, but what you include in it. Although it’s about even on the number of tweets with or without links, those that include links receive 86% higher Retweet rates. From a marketing standpoint, this is a great way to extend a brand’s message beyond just followers. Including images also yields positive engagement.

How: The maxim of “less is more” also holds true for the length of tweets, as those with under 100 characters recieve 17% higher engagements than their more long-winded cousins.

Hashtags (# symbol), used to mark keywords in a tweet, have been shown to increase engagement twice as much. But once again, overdo it, and people get turned off. One or two, and you’re looking at a 21% higher engagement rate than those with more than three. Anything more, and you’ve managed to induce a 17% decrease in engagement.

Perhaps most unsurprisingly, asking for Retweets yields 12 times more of them. Actually spell out the word “Retweet”, and you’ll see a Retweet rate 23 times above average. Nonetheless, the report wonders why less than 1% of brands follow this strategy.

As Tami Dalley, the Vice President of Analytics and Insight at Buddy Media, pointed out in a blog post, “it’s crucial [brands] know best practices for publishing engaging content.” As Twitter has become a major, necessary rung along the advertisement ladder, the report identifies the best ways to make that a reality, getting people to notice, and getting them more involved. What is clear is that the more adept a social marketer is at utilizing and wielding the vast arsenal of Twitter tools, while at the same time understanding the audience, the more successfully this will be accomplished.