Enhancer-derived RNAs (eRNAs) are a group of RNAs transcribed by RNA polymerase 
II from the domain of transcription enhancers, a major type of cis-regulatory 
elements in the genome. The correlation between eRNA production and enhancer 
activity has stimulated studies on the potential role of eRNAs in 
transcriptional regulation. Additionally, eRNA has also served as a marker for 
global identification of enhancers. Here I review the brief history and 
fascinating properties of eRNAs.