It is no secret that many online businesses have so many cooks in the kitchen that they loose track of what they are doing or what they have done. This disorganisation may be detrimental that individual but is a benefit to others who sweep up after them.
What I'm talking about here is the 'Drop Catch' scenario.
Forgetting to renew their domains which have expire is a big market. With these particular sites you will on many occasions get traffic left on the site as a hangover. Business for nothing I say! Many would have booked marked the site and in some instances the traffic can be quite substantial.
Replacing copyright content on the site can bring about a profitable business without any work on marketing at all.
Many sites can be picked up quite cheaply as well, you just have to look for them!