MathML (http://www.w3.org/Math/), OpenMath (http://www.openmath.org), OMDoc (http://www.omdoc.org/) are examples of languages developed for the semantic representation of mathematics on the web and in electronic communications. Such representations can be very exact (for interfacing with computational software), or quite lax and only cater to good typesetting results on the screen. Producing an exact representation is still not widely supported by authoring but the potential benefits for education are large. The JEM, Joining Education Mathematics, thematic network (http://www.jem-thematic.net) is an ongoing 3-years activity aiming at disseminating and raising awareness on using semantic markup for e-content in mathematics.