As I have been using smartphones in my classes, presenting about it, writing about it, and reading about it, I have some concerns.
1. Why limit mobile learning to lower-level drill and kill activities? Spanish teachers can have their students study vocabulary on a topic such as a restaurant via an app. However, they can also use a QR code to show the students a restaurant in Lima Peru and have their students talk about the restaurant.
2. Why limit mobile learning to text-based learning? A common mobile learning activity is to have students use a QR code to go to a web page and read the information. Why not take them to a video or a photo that shows the same learning? Math students can watch a Kahn video instead of reading about the math.
3. Why limit Smartphones to individual activities? Instead of Johnny sitting by himself learning about a country, why not have Johnny and Rosa contrast different pictures of the same country? Johnny has one picture and Rosa a different one.
4. Why limit mobile learning to one small view? English students can search the Internet on their mobile learning device and find a poem about love but these same students can create QR posters in which they show how the human condition of love shows up in a poem, a song, a movie, and a TV show. They can compare/contrast the various types of love.
5. Why limit Smartphones/tablets to just learning when students can use it to analyze their learning? As students do various speaking tasks, they record their scores in a Google document spreadsheet. They can see how well they are progressing at any time. Likewise, they could use an online rubric checklist (Google Doc) to help them assess how well they have written their essay.
How do your students use Smartphone, Tablets or Mobile Learning? Are they limited?
I have 20 Spanish spontaneous speaking/fluency activities at Teacherspayteachers: http://bit.ly/tpthtuttle
My formative assessment books: http://is.gd/tbook Formative Assessment Responding to Your Students, Improving Foreign Language Speaking Through Formative Assessment Successful, and Student Writing Through Formative Assessment
Education with Technology Harry G. Tuttle 
Great post and great ideas for moving past text based assignments and on to more interactive learning. I am a Spanish teacher and I use some of the ideas you listed with my students. We work together to find Web 2.0 tools and apps that allow them to share their work with one another, and use those products to initiate classroom discussion and conversational practice in the target language. We use apps like Fotobabble, Audioboo, Evernote and Hootsuite for Twitter. Their phones are simply tools to create, share an debate content. Thanks again for your great ideas and for sharing those ideas with other educators.