Three studies have characterized the full complement of RNA folding in cells. They find large numbers of secondary structures in RNA, some of which may have functional consequences for the cell.
Molecular biology: A second layer of information in RNA
Silvia B. V. Ramos & Alain Laederach
Nature 505, 621–622 (30 January 2014) http://dx.doi.org/10.1038/505621a