How long should a Facebook post, a Twitter post, a headline, or an e-mail subject be if you’re looking for maximum engagement?

You can read the full post with methodology and outbound links here, or check out this infographic for a condensed version:

This is mostly designed for marketing through social media / web / e-mail, but I’d probably disagree on the 18-minute presentation. I think that’s too long. If you’re going the ol’ PowerPoint route and it’s 1 minute or so per slide, 18 slides seems too much to get a point across. You should be selling what it is, what the value is, and how it could be adopted … and moving on. That’s all people have time for.

Similarly, although this is a bit of a crapshoot, some of the most popular words in viral headlines include you, your, this, what, which, and when. So if you can write a six-word headline with “you/your” in it, you might be golden. For example, NBC News usually puts up something in the AM called “Five Things You Need To Know Today.” That’s one word too many on the info-graphic, but still, you get the broader idea. (Words like “you” and “your” tend to empower the reader, leading them to believe the content they’re about to enter is relevant to them.)

And finally, if you add this infographic into the mix —

— that will tell you when to post. Most of that is fairly self-explanatory: you want to post to things like Pinterest on the weekend (that’s when people contemplate craft projects), things like Tumblr outside of work hours (the posts might require more thought), and things like Facebook/Twitter in the back half of the work day (when people may have cleared much of their to-do list). I read a study once that said Tuesday @ 10am was the best time to send an e-mail campaign, which may be true if you consider that the range for Google+ (which is probably the most tied to e-mail of anything on this infographic) is 9-11am, and Tuesday is a day where you kinda feel like “Well, one down and tomorrow is the middle of the week, so…”

If you combine everything above, then, you should have an idea of (a) how long anything you write should be, (b) what words it should include and (c) when in the day you should post it. One-stop shopping, y’all.