Hair metal is a sub genre of heavy metal which is more chart-oriented than a lot of other rock music. It's often criticised for being entirely based on image and for the musicians being crap. However, the truth is that all genres of music have an associated image; even grunge has its own anti-fashions. The image of the hair metal bands was tight spandex or leather trousers, eye makeup, and long, dyed black or blonde hair, styled with lots of spray to make it look bigger. The required effect was to look like a slightly ugly girl, or in the case of some, a rather attractive girl. In fact, the Aerosmith song Dude Looks Like A Lady was written about Vince Neil, the singer from Motley Crue.
The hair metal genre started because a generation of young people were influenced by Aerosmith and the New York Dolls. Bands in the genre include Hanoi Rocks, Motley Crue, Skid Row, Europe, Bon Jovi (more for the sound than the image) and even Aerosmith themselves when they made their late 80s comeback. To clear up any misunderstandings: Guns N' Roses originally came from the hair metal scene, but had more success than a lot of the other bands because their music was more varied in style and in the theme of the lyrics, so they appealed to people who didn't like hair metal. I would say that GNR are probably the crossover point between hair metal and straight-up heavy metal.
Grunge is said to have killed hair metal, however,many of the hair metal bands are now making a comeback with reunion tours and new albums. The exceptions to this are Bon Jovi, who survived the 90s with a similar amount of success to before, and Guns N' Roses, who basically would have imploded whatever else was going on in the music scene.
Generally the hair metal bands tended to be quite badly behaved- at some point, a lot of the musicians have been involved in drug addiction or alcoholism. For example, during the late 80s every single member of both Motley Crue and Guns N' Roses was addicted to either heroin or alcohol, and Slash was addicted to both, drinking two bottles of whisky every day. Nikki Sixx actually died in an ambulance after a heroin overdose, but was revived with an injection of adrenaline into his heart. This led to the album 'Kickstart My Heart'.
Hair metal tends not to be taken seriously as a genre of music because its lyrics are seen as offensive or stupid. The songs often sound very similar to each other, and there is in fact a particular 'whiny' style of guitar solo that is recognisable in a lot of these songs, although this is partly due to several of the most famous guitarists all using Gibson Les Paul guitars. To be honest, I think that music is there to be enjoyed, and hair metal was written by young guys who wanted to have a good time. It just happens that like a lot of young guys, their idea of fun was to go out and drink, party and get girls. Also- if you don't like it, you don't have to listen to it!
1. Girls, Girls, Girls by Motley Crue is a perfect example of a hair metal song- the video has strippers and motorbikes.
2. The hair metal image of big hair and tight trousers is being brought back by bands such as Towers of London.