About electronica...

       Like many of the major genres, the musical style known as electronica began as a description of a specific type of electronically created music, but is now a blanket term encompassing dozens of sub-genres. Today the word is used in an extremely vague sense, almost always used to describe any type of music that is created with electronic instruments/tools (synthesizers, drum machines, computers, homemade concoctions). Originally the term was used to describe a type of electronic dance music that took the style and moved it from dance floor soundsystems to headphones and audio set-ups at home. Basically, it was an attempt to progress the music from being simple and cold rhythms to intelligent, provoking song-based entities...
     ...With the heavy use of computers and electronic equipment today, the term electronica is thrown around very leniantly and is usually used to describe any act that uses any type of electronic sound devices in their work. Popular styles of today include IDM, electropop, trip-hop, house, downtempo and minimal techno. Many electronic artists, unhappy with the term for its generalization of all electronically created music and the fact that it was created by reviewers instead of the artists or listeners, avoid using term term in favor of 'electronic music', which is not so much a genre but an attribute. [Cited from Wikia]