ADSL Broadband is the name given to the most common type of broadband - broadband internet services delivered to your home over the phone line. With ASDL Broadband, you can download music, pictures and stream video clips from several computers and make calls simultaneously, unlike the old dial-up method where you had to disconnect from the internet if someone wanted to use the phone. The speeds available on ADSL Broadband connections are mostly affected by the distance between your house and the telephone exchange - as a general rule of thumb, the closer you are to the nearest exchange, the better your broadband service will be.
ASDL is short for Asymmetric Digital Subscriber Line, due to the fact that the download speeds and upload speeds differ, with the download speed typically being the faster of the two, hence 'asymmetric'. The reason for this is because consumers of broadband internet services typically download more information than they upload, and so will want faster download speeds, as opposed to the two speeds being equal - by contrast, this type of broadband service is called SDSL, Symmetric Digital Subscriber Line.
When talking about download speeds with regard to broadband services, it is worth mentioning that this does not exclusively refer to how fast you can download large files, like MP3s, for example. Download speeds also refer to how quickly a web page will load over a connection, as your computer downloads information for things such as links, pictures and text from the web, then displaying them on your screen.
A common misconception with regards to the monthly usage limits on some ADSL Broadband products is that you can download up to that amount in MP3s, videos, updates, patches for programs, games etc, but this is not the case - general browsing of the internet also contributes towards your usage limit, so just because you have a 10GB usage cap, don't think that you can start downloading hundreds of music files and think it's OK.
The main advantage of ADSL Broadband is its availability. ADSL connections and services are available practically everywhere in the country - wherever you can get a phone line, you can generally expect to be able to get ADSL Broadband. As ADSL Broadband connections are so plentiful, there are also a greater number of money saving bundle deals available than, say, cable or mobile broadband services, and so generally speaking, ADSL Broadband services often represent the best value for money.
The chief disadvantage of ADSL broadband is that the quality of service largely depends upon how far away your house is from the nearest telephone exchange. The further away you are from your exchange, the slower and less reliable your broadband service is likely to be, due to the physical distance electronic signals have to travel between the premises and the exchange - this is the main reason why broadband connections in remote rural areas typically suffer from slower speeds; some locations are so far away from the nearest telephone exchange that achieving broadband services just isn't feasible. However, it has recently been announced that by 2012, the Government plan to have every home in the UK able to achieve broadband services in some form, using a combination of ADSL broadband lines, as well a fibre optic cable and mobile broadband solutions.