One of the biggest challenges we face as internet business owners is trying to secure domain names that have the keywords we need to help in the Search Engine Optimization process. Over the last few years the number of domains being registered is growing exponentially and Internet marketers are now reverting to domain names that use a combination of dashes and underscores, however you need to be careful using dashes and underscores in the domain names because you can in fact make it very difficult for a client to actually remember your website and come back to it if they did not add it to their favorites. In the long run, this can challenge the ability of your business to grow. From a number of focus groups we have run in Australia and also in conversation with our customers, we have found that a domain using dashes is in fact harder for a customer to remember then one with underscores. One of the core reasons that people find using underscores easier to remember goes back to the bad old days of DOS. The DOS operating system did not allow for names to have spaces and the substitute for spaces was the underscore, consequently people remember underscores between names better than those that use dashes.
If you were choosing a Key Word Rich Name the best choice would be to have the domain with no dashes or underscores. For example if I was trying to setup a domain for a car detailing service in Los Angeles, the best non-company name specific domain for the location would be -
LosAngelesCarDetailingService.com
The key advantage of this name is that customers will easily remember the name and that there are no underscores or dashes. This domain is also far more easier for people to remember if they see the domain