Mobile Learning versus E-Learning - Is There a Difference?

As the potential for technology to enhance learning grows, we often see the phrase mobile learning bandied about. Clearly, the term appears vague as the concept emerges, yet it does call to mind a simple question: How does mobile learning differ from online or distance learning options?
In order to understand the term let’s review the concept as it exists by using the definition supplied from a rather technical article, “Defining, Discussing, and Evaluating Mobile Learning” on the website irrodl.org.
Strictly from a technological standpoint, the term is used for learning that can be delivered and supported entirely by mobile technology. Therefore, among the most common options that could be used for mobile learning would be PDA’s, smartphones and of course, a wireless laptop.
But that begs the question, how does mobile learning differ from other forms of education? Is it really different than e-Learning?
To discuss those options we can immediately begin with the intent of the user. With e-learning, there is a specific intent to learn something - in fact the selection of e-learning is generally based on a desire to acquire a specific set of knowledge or skills. For e-learning we generally add some phrases like tethered (connected to something) as well as learning that is offered in a formal and structured manner.
For mobile learning, the first major difference is that it is un-tethered. It also is defined by learning that is more informal and opportunistic. We can run with that thought and add descriptors like private, situational, and unstructured.
With such thoughts one can clearly see an enormous distinction between e-learning and mobile learning. Most importantly, mobile learning has the potential for even greater impacts than e-learning.
For example, one major change in the idea of learning is that teachers used to deliver some material, or knowledge, with the idea that the student learns the concept “just-in-case.” In fact, most of education is traditionally offered in such a format.
The latest in technology means that a brand new focus is possible, that learning can be delivered “just-in-time.” With the concept of student ownership critical to learning processes, we can see that the latter option should be far superior when working with a classroom full of students. Because not only can the learning be provided “just-in-time,” it can be provided “just-enough” or even “just-for me.”
As a former teacher, I can quickly discern one critical question emerging from the mobile learning format. In such a situation, how does a teacher ensure that the learner retains the knowledge just utilized?
For most educators, a failure to provide an answer to that question will deter them from ever utilizing the mobile learning format.