mLearning in the grand scheme of things

In order to move on to challenges posed by implementation of mLearning, it is necessary to establish in what relationship to other elements of the learning paradigm does mLearning stand. Establishing a systematic relationship between these elements will allow to identify and better comprehend the challenges and possibly suggest solution paths. More importantly, the introduction of a new element into the system may help not only understand its nature but also to deepen the understanding of already present elements and even help solve some of the exciting issues thus balancing out the system. 

Probably the most logical way of thinking about mLearning is as of an extension of eLearning. Both are grounded in technology and both induced and continue to induce changes in the teaching/learning paradigm. Granič et al. (2009) suggest the following placement of mLearning in the system:

(Source: Granič, A., Čukušič, M., & Walker, R. (2009). mLearning in a Europe-wide network of schools. Educational Media International, 46(3), 167-184.)

They propose to view the move from distance learning to electronic learning to mobile learning in terms of evolution (Granič, Čukušič & Walker, 2009). The evolutionary aspects are both innovations in information technology and subsequent changes in the educational theory aimed at incorporation of these innovations in order to accommodate new learner needs. 
This approach seems valid enough. However, such activities as the use of mobile devices in class for collaboration or immediate feedback does not fit anywhere in the figure. If the emphasis in the definition of mLearning is put on the presence of a mobile device and not on quick and sporadic access to fragmented information, than the following figure might be more suitable for identifying the place of mLearning:

Fig 1. mLearning in relation to other elements of the system.

Three notes should be made here with regards to the figure:

• definitions of elements present are numerous and varied and their validity is contestable depending on the goals of any given work. Here, the approach is rather straightforward: in blended learning the proportion of f2f knowledge transmission is higher than in eLearning. Distance learning is an overreaching frame that involves such higher-order activities as education administration through ICT; it may or may not be present in blended learning.
• technology-free traditional learning is not included because it becomes increasingly difficult to imagine an efficient classroom where no use of the ICT for educational purposes is made whatsoever by any of the stakeholders. So, this traditional model is subsumed by the blended learning model.
• blended learning partially overlaps with eLearning because it may or may not include activities more typical of an eLearning model.

Furthermore, Granič et al. (2009) view mLearning and online learning as two separate subcategories of eLearning. Online learning can be characterised by access to formal (such as LMS and VLE) and informal sources from a desktop/laptop computer, by longer periods of time taken to process the information and by work that requires more concentration and in-depth analysis. But than, mLearning could be suggested to overlap with online learning as well based on at least one of the characteristics: access to sources. Mobile devices today have enough power and screen size (consider iPhone 6+ as an example of another victim fallen to the phablet trend) to allow stakeholders to access information online while providing an experience similar to that of a desktop/laptop computer. This experience can be and often is enhanced by purpose-specific apps and by HTML-coded pages that adapt their layout according to the device they are accessed from. 
The distinction between mLearning and online learning is further blurred by intermediary devices, such as tablets. They allow to combine sporadic access patterns with the periods of longer concentration on the task thanks to, among other factors, the increased convenience of typing on a lager screen. It can be suggested that, in time, the need for the methodological distinction between mLearning and online learning may disappear. After all, simplification is one of the key elements of well-balanced working systems.  

mLearning stretches both left and right in the figure above to overlap with blended learning and eLearning thus establishing its ubiquitous presence in the same manner as smartphones/tablets are currently present in our lives. Indeed, if a smartphone/table is always with you anyway, it makes all the more sense to make use of it on all levels of the system; this notion is represented by the mLearning circle being superimposed on all other elements of the figure it has contact with.

References:

Granič, A., Čukušič, M., & Walker, R. (2009). mLearning in a Europe-wide network of schools. Educational Media International, 46(3), 167-184.