Toplining is a very contemporary form of – usually collaborative – song writing whereby the song (melody and lyrics) is overlaid on a pre-made set of beats. Due to technological change many songs in mainstream music genres such as pop, R&B and Hip Hop were created as instrumental beats were then toplined.

Although the lo-fi genre has a very contemporary feel it actually has a long history.
The genre can be traced back to the early 1950s when R&B artists often recorded songs crudely and quickly. The raw D.I.Y sound quickly became associated with youth. In the 1970s and 80s punk and metal bands often purposefully recorded tracks with poor equipment and with the intention of sounding distorted and structurally unconventional.
By the late 1990s new technology was allowing young artists and music producers to make new kinds of lo-fi music using computer software to create beats and import samples. The results have sometimes been strange but also often very rich in texture and tone. 
 

Lo-fi AKA Chill Hop has become an internet sensation. It is all over Youtube where the genre has become an amalgam of the visual aesthetics of Japanese anime (prosaic scenes of a child writing a diary or staring out of her bedroom window) and dreamy synth beats and ethereal vocal samples. The audio visuals are looped to create a repetitive atmospheric ambience.