Lots of people out there are trying to make money by blogging, with varying degrees of success. For bloggers who have already gotten a small foothold in the search engines, the question of building an audience becomes the next big challenge. One of the true keys to success in blogging involves building a critical mass of readers who will recommend your blog, so it gets a market share that attracts advertisers or syndicators who are willing to pay you for your work.

One of the better ways to get an audience is through market research, and the top free market research tool online is the Google Keyword Tool (AKA the Google Adwords Keyword Tool). This tool actually tells you what people are looking for, and even gives seasonal search trends information if you know how to look for it. The keyword tool also suggests alternative keywords that may get you an even bigger audience, or new set of topics with a guaranteed interest base.

For example, let’s say that you want to get more readers who are interested in “online marketing.” Using the Google keyword tool, you would type in the phrase, and make sure to click the box for “use synonyms.” After waiting about 10 seconds for results, you should get two lists. The first will be more relevant matches, and the second will have related terms. There are also columns for local and global search volume. If you click on the top of either column, the results are sorted by popularity.

Our search revealed the top 10 terms to be:

online marketing
online marketing business
online advertising marketing
online marketing promotion
online marketing services
online marketing company
online marketing media
online marketing search
online marketing strategy
online marketing agency

Meanwhile, the top 10 related terms were:

marketing
internet marketing
business marketing
marketing advertising
website marketing
branding
email marketing
internet marketing tools
marketing services
web marketing

For a blogger, the keyword tool can be a goldmine, since the June 2009 results from this tool showed that “internet marketing” gets 1.8 million searches per month vs. 673,000 for “online marketing.” For a power blogger who is looking for an audience, either one of these terms would be fine for inclusion into a blog, but one term gets nearly 3 times the audience of the other one. Aside from the small sample of results here, there are also several dozen keywords and variations in the rest of the list that make for good blog topics.

The keyword tool also lets you see a diverse selection of ideas and desires built around these words. You can look through the list of search results and find out how many people in your sample base are thinking about something else when they type in “online marketing,” and you can hone your subject to capture the audience that is best for you. If you are blogging about “online marketing strategies” you can feed the keyword back into the search tool, un-check the synonyms box, and see more relevant results.

There are also ways to use the keyword tool to see the relative value of a word or phrase. For people who make money off their blogs with Google Adsense, this can be a critical way of increasing the average payment for every click. Under the dropdown that says “choose columns to display” you can pick the “show estimated average CPC” column, and you will see a relative keyword cost next to each phrase. In the June 2009 results, “online marketing programs” has an average cost per click of $13.72, so that may be an attractive one to go after. Conversely, if you are an eccentric billionaire and want someone to visit your blog, you can actually buy this term on Adwords and send people there.

The “Search Volume Trends” column is also quite valuable for people who are blogging about seasonal topics. (You should always mouse over the months on the graph, because they are not presented in a January to December format.) It would appear that marketing terms peak in May and June, but drop in August. Given that blog postings sometimes take a few weeks to get traction in the search engines, you can plan out your topics so they get cached and indexed in the search engines during these peak periods. If your blog gets picked up and indexed more quickly, you could even have a series based around a topic that keeps people interested and gets more search saturation.

Prior to keyword tools like Google, research was based on surveys and focus groups. The problem these information gathering methods is that they can be skewed by the way questions are written, the presence of dominant focus group members, or even the attractiveness of the person asking the questions. People might even be afraid of expressing their true opinions to someone on the other end of a phone. In some cases, a market research firm may be told to come back with a certain conclusion, and it can structure questions and focus groups to return the “right” answer. Search engine queries, for the time being, are based on actual user interests. Nobody feels the need to impress a search engine or lie to it , because the engine is delivering results that they “want.” When it comes to picking an audience for your blog, of finding out a level of interest, keyword research tools will likely give you a better sample than any opinion poll, and give your real numbers at the same time.

Once your blog gets a respectable audience, you can also use keyword research to measure your own popularity. For instance, you could put your own name, or the name of your blog, into the tool to see how many people are looking for you. Just remember that your core audience already remembers your URL or has you bookmarked, so the results you see are more likely to be people who have heard about you and want to know more. Even better, you can track the popularity of your ideas if you have original topics that are not based on current keyword trends. Every day, people read blogs and then go back to the search engines to research concepts that they have learned about, and you can go back into the tool the next month to see if your concepts are gaining a market share. For people who are blogging to change the world “one reader at a time,” there is a lot to be said for this kind of intellectual market intelligence.