The discussion around mobile marketing often centers around smartphones, but it really extends to ereaders and tablets as well. eMarketer recently released data that highlights the growth of each of these mobile devices in 2011 and into 2012. US smartphone users will increase from 90 million in 2011 to 107 million in 2012, ereader users from 33 million to 46 million, and tablet users from 34 million to 55 million (tweet this stat). "More and more," eMarketer writes, "marketers are realizing that traditional notions of interruptive advertising need to be rethought. Many are experimenting with branded videos, games, apps, and online contests that blur the line between advertising and content."

We also learn that readers expect to experience a seamless transition from one device to another, so it's crucial to understand the way each of these mobile devices can be leveraged to showcase your content. Even if you're not yet focusing on optimizing for every one of these devices in your mobile marketing strategy, it's important to understand some of the content formats you should consider in 2012 so you can prioritize your content creation efforts accordingly.

5 Content Formats That Rock on Mobile

1.) Ebooks - With the launch of Amazon's Kindle Singles in 2011, the short ebook gained the spotlight it deserved. Best suited for ereaders and tablets, ebooks are an engaging content format that lets you perform a deep dive into a topic to provide actionable information for your readers. If you're already an avid creator of written content, there's a low barrier to entry when venturing into ebooks. With just a little design knowledge, you can create an engaging ebook for your prospects that will help you generate leads and boost your brand's authority.

2.) Cartoons - Great content is helpful and engaging; truly remarkable content does that with a handful of words, and oh yeah, can make you laugh in the meantime. That's what is so awesome about comics! They're visual content that perform really well on mobile devices, they illustrate a complicated concept in very few words, and they somehow also make you giggle. If you have an idea for a cartoon related to your industry but you're held back because you're not an artist, reach out to your network to help you find someone. The production cost is low, but these things can go viral fast!

3.) Videos - Video streaming now makes up 39% of all mobile traffic, and not surprisingly, YouTube accounts for 52% of all global video streaming. This data shows that the smaller screen isn't stopping people from watching video on their mobile devices, and in fact, eMarketer projects that in 2012, 54.6 million people will view video on their mobile devices. What does this mean for marketers? Video ad spend aside, it means incorporating video production into your content creation mix is a wise move, especially if you're promoting that content socially and maintaining your YouTube channel. If it seems like video content isn't applicable to your business, think twice. Have you considered a how-to video? A product demo? Even a holiday card in video format? Creating video content will take more resources than some of your written content, but it is an ideal content delivery format for mobile users.

4.) Infographics - Infographics are a great way to translate written content (particularly data points) into a visual format that is easier to digest on ereaders, tablets, and smartphones. Not to mention that infographics are fun to read, so people are more willing to share them with their networks. Their long, vertical format is also ideal for the rectangular mobile screen, eliminating the need for users to scroll right and left.

5.) Podcasts - While your podcast could certainly be video, also consider an audio podcast for lower production costs. Both of these formats are ideal for mobile devices, which are usually not far from a pair of headphones and are a welcome distraction for your on-the-go audiences. What's so great about podcasts is that the best ones are just genuine, casual conversations, so instead of writing a script, all you need is an interesting topic to riff on. As your audience grows, so will your reach as they share your podcast with their networks. To get more out of your efforts, encourage your audience to engage with you; they can give feedback on the podcast itself or be invited to speak on your podcast about issues relevant to your industry.

What's great about these content formats is not just that they're particularly well suited to your mobile audience, but they totally rock on your website for non-mobile users, too!

What content formats do you enjoy most on mobile devices? Have you started creating mobile-friendly content for your readers?

Image credit: Ted Murphy