Advantages:
* Can be very cheap start up costs (domain $8,hosting $10) when compared to other business such as owning a shop,for example a pizza takeaway has to buy ovens,ingredients etc..
* You can run your business from anywhere
* Low overheads (hosting and maybe staff costs)
* The internet is still a open market,lots of opportunities for new business models exist.
Disadvantages:
* Low barriers to entry which means that it is easy for someone to set up a website and compete with you
* Business models can easily be copied,look at youtube and how many copys of their site exist.
* Can take a bit of time to train yourself,for example if you were to start a sandwich shop you can pretty much start making sandwiches without much trouble whereas to make a website you need a bit of knowledge and skill