Patterned media, where the single domain recording bits are magnetically isolated from each other, offer the possibility to overcome many challenges faced by the other storage technologies, such as to obtain stable signal-to-noise ratio when the track width is reduced. The patterned media is likely to be the future media with high recording density and this has stimulated exploitation of different technologies to fabricate small featured magnetic materials. In parallel with the development of nanopatterning techniques there has been substantial progress in understanding and modelling the magnetic properties of small nanoparticles and patterned nano-dot arrays. The reduction of dimension leads to dramatic differences in micro/nanostructure, coercivity, anisotropy, and magnetic moment etc which attracted enormous attention from both academia and industry in many areas and spans far beyond the information storage field. Hence the paper is organised in the following way: In section I, as the patterned media is the most promising application for nanomagnet array, we briefly overview the data storage principle and storage media. Section II describes several alternative imprinting and pattern transfer technologies. Section III introduces the spin configurations, magnetization reversal properties of small magnets. Finally, in section IV a summary of current and possible future development in this area is outlined.