Soca music is music to jump, wave, and "wine" to, amongst other ways of dancing. Most soca songs are written to generate crowd response and therefore a soca song which fails to give rise to these particular ways of dancing (jump, wave, wine, etc.) is usually not a good one. Such a song won't be given much radio airplay. "Wine" is derived from the word "wind" and "wining" is a type of dance consisting of hip movements. Usually there's bodily contact.
In a typical fast soca (power soca) song, soca artists urge the audience to jump, and to wave rags and flags. Common lines used by soca artists in their songs are "put your hands in the air" and "wave your rag". These phrases have been overused in soca music and have become cliches. A soca artist has to be more and more creative nowadays and has to think out-of-the-box (cliche), to be able to come up with genuine reasons for the audience/crowd to jump and wave or heed his dancing instructions. Otherwise it's the same kind of song over and over.
Many soca songs include themes like love, peace, and unity. Examples of songs based on these themes are Alison Hind's "Togetherness" and Mantius' "We Making Love" (shameless plug). On the other hand, there are soca songs which encourage over-indulgence in alcohol and some have heavy sexual connotations. But since soca music is centered around a festival called carnival, what may seem negative to an outsider is taken in good spirit by carnival lovers.
Machel Montano is generally regarded as the biggest soca artist. He is from the Caribbean island of Trinidad and Tobago and commands large audiences in all the Caribbean islands, as well as London, Canada, New York, and Miami. Despite his huge success amongst West Indian (Caribbean) audiences, he is yet to make a very significant impression on mainstream markets. So largely, soca is still underground music, for want of a better word. It's amazing how a genre could be so huge in the Caribbean, as big as reggae music, but not be able to penetrate larger markets.
Having said this, one soca artist who has made a dent on the mainstream music market is Kevin Lyttle from St Vincent with the song "Turn Me On". The Baha Men with "Who Let the Dogs Out" (originally recorded by Anslem Douglas), Collin Lucas'Dollar Wine and Buster Poindexter with "Hot, Hot, Hot" (originally recorded by Arrow" are other hits that have made it big on international markets. These are a few hits which have gone mainstream but the overall impact of soca is average. It comes no way close to what other Caribbean genres like reggae and reggaeton have done.