The overall Google Network is made up of the Search Network and the Content Network. Your ads will appear on the Search Network if you have so chosen this in your campaign settings. In these cases, the user’s search query words determine where the ads are targeted. These are the ads that show up in a column next to search engine results, like the ones seen in the screen shot. The higher the keywords’ Quality Scores, the higher ads show up in these columns.

As for the Content Network, the eligibility of your ad to show up on a particular content site, and its location on that site are determined by your keyword’s Quality Score for content, which is based on past performance of your ad on this site, and on similar sites. The Quality Score for Content is also based on relevance to the keywords and those of the ad group on this site.

Using the Google Keyword Tool, and optimizing your ads so that they are highly keyword-specific will help boost your keywords’ Quality Scores.

The only real certainty is that keyword stuffing (forcing a high percentage of keywords into page content to the detriment of the content itself) is not good and can result in a penalty from various search engines. Just about any search will give you first page results that have widely varying keyword percentages, including, believe it or not, 0%. Over the long term, good content rises above keyword-stuffed pages with little useful information on them.

For example, if you search on the keyword “beekeeping,” the top result, as you see in the screen shot, is the Wikipedia article, which has a keyword density of about 1.4%. The second-ranked search result is http://outdoorplace.org/beekeeping/citybees.htm, which has a keyword density of 0.6%. The third-ranked search engine result has a 3.7% keyword density.

This in no way suggests that 1.4% keyword density is “optimal,” but that there are factors other than keyword density at work in determining search engine rankings. There is no escape from the need for good content regardless of keyword density.

• Though you will focus on your broadest terms in the big picture, do include a mix of long-tail (three words or longer, specific) phrases in your link building. You will see much faster results with long-tail words obviously, and will generate some traffic quicker than the time it will take you to move up in SERPs for the competitive broader terms. This could be ‘Benjamin Moore latex paint’ instead of ‘paint’, or this could be “best latex paints by the gallon”. Point your specific terms to their respective, already-optimized, internal page.

• The most popular terms, the ones that show the most traffic using your favorite keyword tools, are not always the best choices for your particular site for conversion. What items bring you the most profit? What items are less competitive where you can rank quickly? You may want to rank for “Purdy paintbrushes” because they are searched more, but your profit is highest on the cheap no-name brushes you offer “cheap wholesale paintbrushes’

• Which terms are the most clickable for your business? (clickable is spell-check highlighting as though it is not a word! perfectly good word to me!) It would be fantastic to rank highly for “adoption support groups” since the traffic is good and it is an attainable goal, and you do have a support group or two in your directory, but when your listing is displayed for your adoption directory, if the wording is not going to be compelling and all about that term (such as “comprehensive list of adoption and foster parents support groups”), then you will be skipped. High rankings do you less good if the listing is not clicked.

• Watch your AdWords results for ideas and trends, but keep in mind that you may not be getting clicks for important keywords just because your bid is lower on that term. Use the results, but use common sense as well. Same thing for your current organic traffic. We had a client that did not want to use a term because he had no traffic for that term. Well without the ranking, of course there is no traffic. It was an important term and we convinced him to include it.

• Choose words that stick, and drop words that don’t. If you are moving up for some words more quickly than others in your linking and SEO efforts, build on those first while you have the momentum.

Keyword Discovery offers a paid search tool that is quite robust. They offer a free version which is limited in features but still quite usable and helpful. The paid version I have not used, but the features look like you can really get down and dirty with your research, looking at keyword by niche, showing the most popular searches in a particular industry.

http://www.keyworddiscovery.com/search.html

Wordtracker is the other popular paid keyword suggestion tool, and their free version is quite useful. you can only enter one word instead of comparing multiple words. Wordtracker offers a free trial for their more robust product for 7 days.

http://freekeywords.wordtracker.com/

SubmitExpress has a free tool called Keytracker that gauges the traffic of words, comparing those two popular keyword tools. You can enter more than one keyword, and It makes suggestions and shows the traffic for suggested or similar words as well.

http://keywords.submitexpress.com/keytracker.php

For keyword suggestions, Google offers its keyword tool for free, which will suggest keyword combinations based on either phrases you enter, or will analyze an existing web page. Then it does show the search traffic for those words. Another helpful free tool, recommended.

https://adwords.google.com/select/KeywordToolExternal

Microsoft’s Adcenter offers the Keyword Forecast tool. It will compare traffic for a few keywords in graph form, and does not require you to type in letters verifying you are a human, saving time for a quick look. The data seems to be about a year old though:

http://adlab.msn.com/Keyword-Forecast/Default.aspx

SEO Book offers a keyword research tool that compares data from many sources in one view. You can get lost in this one. You can only enter one word at a time, and it does not make the best suggestions compared to the others, but the info correlated is very robust, linking to the different keyword tools and search engines that it used to populate the info, showing the other suggestions and traffic from search engines. Fun toy.

http://tools.seobook.com/keyword-tools/seobook/