Any of the small (10-200 nm), heterogeneous, highly dynamic, sterol- and sphingolipid-enriched membrane domains that compartmentalize cellular processes. Small rafts can sometimes be stabilized to form larger platforms through protein-protein and protein-lipid interactions. [ http://www.ncbi.nlm.nih.gov/pubmed/20044567 http://www.ncbi.nlm.nih.gov/pubmed/16645198 ]