RNA modifications, especially methylation of the N6 position of adenosine (A)--m6A, represent an emerging research territory in RNA biology. m6A is a post-transcriptional modification of RNAs, which is catalyzed by the mRNA: m6A methyltransferase complex containing three individual components and is the most common form found in the internal sequences of mRNAs in eukaryotes. Latest study showed that the fat mass and obesity-associated protein could remove the methyl group, indicating that the modification is reversible. Importantly, inhibiting or silencing the methyltransferase will cause significant changes of phenotypes. However, due to limited detection methods, the mechanism of m6A has not been figured out yet. Next-generation sequencing combining with IP (immunoprecipitation) technologies makes it possible to detect m6A modifications in a large scale. Here, we reviewed recent progresses of m6A studies including the discovery of m6A, mechanism of biosynthesis, tissue and genome distribution, detection methodology and possible biological functions. We also compared three IP-seq technologies that are currently widely used, and summarized the challenges in m6A studies.