You get a great idea for a web site, you get overtaken by the enormous potential (for money or entertainment, it doesn't matter which) and you rush headlong into creation of the site, researching the content, getting pictures and texts to fill your space.
Not all is well with paradise though. It seems that one or more people have run around registering every which way of every name you can think of. They have no web site, instead they have a default page saying "This site was registered by one of our customers", or worse still is the "under construction" sign we see everywhere.
The whole Internet is littered with these named but unused sites.
No problem you say to yourself, I'll email the chap and ask how much he wants. Taking note that a domain name costs anywhere from $5 to $70 you fire off your email. The reply is usually "make me an offer", so feeling generous you offer $200. Of course the reply you get back is to be expected, "I was thinking more like $25,000".
Duh, it seems this is the attitude throughout. Half the Internet is 404 not found or porn, the other half is dead domains pointing to nowhere or under construction.
All of the good domain names have gone or are being held hostage by people that have no plans to do anything with them except make big bucks by selling them to people that are creative enough to make use of them.
The lights are on but nobody is home...
Aside: Not all good domain names are gone. I was surprised to find FatBird.com available, and I recently bought KingCoder.com for my contract software development site. There is hope, not only do you need to be creative with the web site but you also need to be creative with respect to the domain name.