The phrase 'Mod' is not a particularly useful one musically, it is however a word that best describes the youth movement and ensuing sub-culture of the mid-60's, whereby young teenagers would don smart suits and dresses to escape working class stereotypes regarding fashion whilst listening to raw and raucous R&B / Soul influences (in contrast to the stronger Blues influences of their Rocker contemporaries). Bands such The Who and The Small Faces as well as singers such as Georgie Fame are associated with the movement.
The Mods frequently clashed with the rockers who didn't like the attention to dress and fashion sense of the Mods which they saw as effeminate. The rivalry led to violent clashes and fights often over-hyped by the media.
After the mod movement dissolved once the love generation changed the music scene, many became suedeheads, also known as 'Hard Mods'. The main musical influences involved here were Ska and Reggae which was brought over by West Indian immigrants in the 60s and 70s. These went on to form the rudeboys of the late 70s. In the North of England, Mods continued to follow soul, the Twisted Wheel in Manchester became known as the birth place of Northern Soul.
The Jam fronted by the Paul Weller became the figure head to a new wave of mods which the press labelled a mod revival drawing comparisons to the original movement, though this was never accepted at the time as the preferred label was that of being a Modernist. A new generation of Mod-esque bands emerged including The Chords, The Lambrettas, Secret Affair and more. These bands drew influences from R&B group Dr. Feelgood (as did the punk movement) and also Generation X. This sparked a Mod Revival in the US, especially in Southern California where bands such as The Untouchables championed the movement. The Mod Revivalists often clashed with Teddy Boy revivalists, Punks and Casuals.
The Mod Movement is still vibrant, though somewhat diminished since its peak. The influence of the Mod Revival are still present in today's music industry and massively influenced many of the bands involved in the Britpop era of the 90s however whilst there are many blues-rock bands, none play in a mod style. The Rifles are arguably the closest to a modern day Mod band, drawing on blues influences and playing in a post-Mod style. .