Given a lack of research addressing especially Spanish-English online language mixing -a startling fact given that Spanish is now the third Internet language-, this study examines and compares data from three distinct CMC sources (e-mail, blogs, and social networks including Facebook and Twitter) among Spanish-English bilinguals in order to further investigate the still fairly novel field of “electronic code-switching”, supposing that it will fulfill many of the socio-pragmatic functions traditionally attributed to oral code-switching along with, possibly, other uses idiosyncratic of CMC. Moreover, it proposes to underscore the cultural nature of code-switching, a pivotal element that has often been neglected in the quest for grammatical restrictions.