Dashes vs. Underscores?

There has been many questions concerning this topic. So what is the correct way to use these 2? I did quite a bit of research on this topic the last couple days and stumbled a-crossed the nail in the coffin so to speak.

Before I get to the solution, a brief rundown of what these 2 characters are and how they are used. A (-) dash and (_) underscore are used in providing a space between to keywords in a URL. For example I might have a page called "horseracing.asp". I could break up "horse" and "racing" by doing the following: "horse-racing.asp" or "horse_racing.asp" Either form work to create a new page. The question we need answered is, what character actually separates the keywords in search engines, so they reflect 2 separate keywords.

After much digging, the solution primarily came from a well known forum that stated that a Google representative described it as "Underscores are not delimiters, dashed are". Although not giving out the exact answer, one can assume that when using an underscore it acts as another letter and would create one big keyword. When using a dash, it is looked at as a delimiter (break) between keywords.

The simple solution, use a dash between all keywords if you want to represent them as separate keywords.