DavidDragon - Profile

Ultimately, you need to have one heck of a load of good content. If you don't have great content, you have nothing. This is the case whether you're a local business with a website, or someone hoping to make money strictly through an ad-supported website (which it sounds like you are). You've got to have good content. This is why so many businesses and entrepreneurs freaked out with all the Google algorithm updates over the past couple of years - they were trying to game the system, make an easy buck, but they hadn't invested the time and effort to actually have good content in the first place. If you do that right, then you really don't need to worry about any future algorithm updates.

I agree with sjr4x4 that both SEO and SEM are "part of the same pie," but a more accurate description might be that SEO is just a part of SEM. SEO (search engine optimization) is about getting your website to rank highly in the Google results (yes, I know there are other search engines, but Google remains far and away the most widely used).

SEO can involve such things as all content that is on your website, as well as offsite content (including backlinks and citations) that helps to boost the authority of your site in Google.

Other things which would fall under the SEM umbrella but which are not strictly speaking "SEO" include things like pay-per-click advertising (Adwords), local directory listings (Google+ Local), and video (YouTube).