Microlearning deals with relatively small learning units and short-term learning activities. Generally, the term "microlearning" refers to micro-perspectives in the context of learning, education and training. More frequently, the term is used in the domain of e-learning and related fields in the sense of a new paradigmatic perspective on learning processes in mediated environments on micro levels.
In a wide sense, microlearning can be understood as a metaphor which refers to micro aspects of a variety of learning models, concepts and processes.
"No matter if learning refers to the process of building up and organizing knowledge, to the change of behaviour, of attitudes, of values, of mental abilities, of cognitive structures, of emotional reactions, of action patterns or of societal dimensions, in all cases we have the possibility to consider micro, meso and macro aspects of the various views on more or less persisting changes and sustainable alterations of performances." (Hug 2005, p. 4).
Depending on frames and domains of reference, micro, meso and macro aspects vary. They are relational concepts. For example, in the context of language learning, one might think of micro aspects in terms of vocabularies, phrases, sentences, and distinguish them from situations and episodes (meso aspects) and socio-cultural specifics or complex semantics (macro aspects). In a more general discourse on learning, one might differentiate between the learning of individuals, group learning or learning of organizations and the learning of generations or societies.
Furthermore, microlearning marks a transition from common models of learning towards micro perspectives on and the significance of micro dimensions in the process of learning. The microlearning approach is an emergent paradigm, so there are no hard definitions or coherent uses of the term yet. However, the growing focus on microlearning activities can be seen by web users' activities on the subject, who tag their corresponding weblog postings and social bookmarks with the term "microlearning" (check the corresponding Technorati and del.icio.us tags for examples).
As an instructional technology, microlearning focuses on the design of microlearning activities through micro steps in digital media environments, which already is a daily reality for today's knowledge workers. These activities can be incorporated in learner's daily routines and tasks. Unlike "traditional" e-learning approaches, microlearning often tends towards push technology through push media, which reduces the cognitive load on the learners. Therefore, the selection of micro learning objects and also pace and timing of microlearning activities are of importance for didactical designs.
Characterization of microlearning 
Microlearning can be characterized as follows:
- Microlearning processes often derive from interaction with microcontent, which takes place either in designed (media) settings (e-learning) or in emergent microcontent structures like weblog postings or social bookmark managers on the World Wide Web (Mosel 2005).
- Microlearning can be an assumption about the time needed to solve a learning task, for example answering a question, memorizing an information item, or finding a needed resource (Masie 2006). Learning processes that have been called "microlearning" can cover a span from few seconds (e.g. in mobile learning) up to 15 minutes or more. There is some relation to the term microteaching, which is an established practice in teacher education.
- Microlearning can also be understood as a process of subsequent, "short" learning activities, i.e. learning through interaction with microcontent objects in small timeframes. In this case, the design, selection, feedback and pacing of repeated or otherwise "chained" microlearning tasks comes into view.
- In a wider sense, microlearning is a term that can be used to describe the way more and more people are actually doing informal learning and gaining knowledge in microcontent, micromedia or multitasking environments (microcosm), especially those that become increasingly based on Web 2.0 and wireless web technologies. In this wider sense, the borders between microlearning and the complementary concept of microknowledge are blurring.
Dimensions of microlearning 
The following dimensions can be used to describe or design microlearning activities:
- Time: relatively short effort, operating expense, degree of time consumption, measurable time, subjective time, etc.
- Content: small or very small units, narrow topics, rather simple issues, etc.
- Curriculum: small part of curricular setting, parts of modules, elements of informal learning, etc.
- Form: fragments, facets, episodes, "knowledge nuggets", skill elements, etc.
- Process: separate, concomitant or actual, situated or integrated activities, iterative method, attention management, awareness (getting into or being in a process), etc.
- Mediality: print media, electronic media, mono-media vs. multi-media, (inter-)mediated forms, etc.
- Learning type: repetitive, activist, reflective, pragmatist, conceptionalist, constructivist, connectivist, behaviorist; also: action learning, classroom learning, corporate learning, etc.
(Hug 2005, used with permission)
Examples of microlearning activities 
- reading a paragraph of text, e-mail or sms
- listening to an informational (short) podcast or an educational video-clip
- viewing a flashcard
- memorizing a word, vocabulary, definition or formula
- sorting a set of (microcontent) items by (chrono)logical order
- selecting an answer to a question
- answering questions in quizzes
- playful learning with micro-games
- composing a haiku or a short poem
Microlearning applications (examples) 
- Screensavers which prompt the user to solve small series of simple tasks after a certain amount of inactivity
- Quizzes with multiple choice options on cell phones by use of sms or mobile applications (java midlets, symbian)
- Word of the day as daily RSS-feed or e-mail
- Flashcard-software for memorizing content through spaced repetition
See also 
- Gassler, Gerhard (2004): Integriertes Mikrolernen. MPhil. thesis, University of Innsbruck (Austria).
- Gassler, Gerhard; Hug, Theo & Glahn, Christian (2004): Integrated Micro Learning – An outline of the basic method and first results. In: Auer, Michael E. & Auer, Ursula (eds.): International Conference on Interactive Computer Aided Learning, ICL 2004, Sept. 29 – Oct. 1, 2004, Villach, Austria (CD-ROM).
- Gstrein, Silvia & Hug, Theo (2005): Integrated Micro Learning during Access Delays. A new approach to second language learning. In: Zaphiris, Panayiotis (ed.): User-centered computer assisted language learning. Hershey: Idea Group Publishing, pp. 152–175.
- Hagleitner, Wolfgang; Drexler, Arthur; Hug, Theo (2006). Evaluation of a prototypic version of Knowledge Pulse in the context of a management course. Paper presented at the MApEC (Multimedia Applications in Education Conference) 2006, September 4–6, FH Joanneum, Graz, Austria.
- Hug, Theo; Lindner, Martin; Bruck, Peter A. (eds.) (2006): Microlearning: Emerging Concepts, Practices and Technologies after e-Learning. Proceedings of Microlearning 2005. Innsbruck: Innsbruck University Press, 2006.
- Hug, Theo (2005): Micro Learning and Narration. Exploring possibilities of utilization of narrations and storytelling for the designing of "micro units" and didactical micro-learning arrangements. Paper presented at the fourth Media in Transition conference, May 6–8, 2005, MIT, Cambridge (MA), USA.
- Masie, Elliott (2006): Nano-Learning: Miniaturization of Design.
- Mosel, Stephan (2005): Self Directed Learning With Personal Publishing and Microcontent. Constructivist Approach and Insights for Institutional Implementations. Paper presented at the Microlearning 2005 conference, June 23–24, 2005, Innsbruck, Austria.
- Weber, Charles M. (2003): Rapid Learning in High Velocity Environments. Ph.D. thesis, Massachusetts Institute of Technology (M.I.T.) / Cambridge (U.S.A.).