After all, in any marketing campaign, true bottom line should be your ROI, return on your investment. That's how you'll know if your marketing efforts are really working, or if you need to go back to drawing board and try something new.

Recently, I was introduced to a new ROI calculating service called KeywordTool. It covers both pay-per-click engines and regular engine results.

To write article, I interviewed Chris Genge of KeywordTool (http://www.keywordtool.net), and he took me on a tour of service itself.

Question: Please explain what KeywordTool is and what it really does.

Chris: "Deciding which keywords best suit each Web site and which ones specifically will generate sales/conversions is perhaps toughest job in SEO. Tools like Word Tracker are a great help in narrowing down keyword selection, but then what?

"In past, decisions were not based on facts but mostly speculation. This gave people no alternative but to promote or bid on larger keyword groups. We used a shotgun approach in hopes of increasing sales, with no way of telling which keywords were adding to our bottom line!

"A common saying in advertising is: `In any good campaign, 50% of all advertising dollars are wasted, but which 50%?' KeywordTool can answer this question for keyword promotion campaigns.

"KeywordTool's tracking service tracks conversion or sales performance of keywords on search and pay- per-click engines, showing which keyword phrases are actually converting into customers and from which search engines. It is not a visitor tracker; instead, it determines keyword performance.

"With this keyword referral/conversion rate information, one can then fine tune their keyword choices and streamline promotion and bidding expenses to increase efficiency, sales, and profits, or in other words...the bottom line.

"KeywordTool is an online service that gathers information about your Web site referrals and sales/conversions. Using your private user name and password, you can then access stats so you can review information and make informed decisions about how to continue your online promotion.

"KeywordTool is designed for use with SEO and Pay-Per- Click (PPC) campaigns. It's well suited for both."

Question: Is there a way that we can see a demo of how service really works?

Chris: "Go to http://www.keywordtool.net At top of page, you will see log in. Use username of "keywordtool" and password of "demo" to access demo.

"The first page is list of search engines that have sent referrals to specific Web site you wish to have monitored. Only search engines that have sent a referral will appear on listed sites. New search engines will appear as referrals are sent.

"The `Create details' or `Edit details' in first column is where you would click to configure your search engine settings. This is where you tell KeywordTool what your average cost per click is for each search engine you want to calculate. This can be filled out after some data has been gathered.

"The search engine column is list of only those search engines that have referred visitors to your Web site. You will notice that KeywordTool will also differentiate between regions for those search engines that are regionalized.

On face of it arguments appear to be sound. Google obviously has several billion pages in it's database and could, it appears, easily determine if content is duplicated. It also seems, again on face of it, that it's reasonable to check for duplicate content, as this is "mark of a spammer" and not necessary on web with hyperlinking available. At least, this is common wisdom.

However, sometimes what seems reasonable and possible is not: not by a long shot.

Let's begin with technical side of things. You've got domain x and domain y with exactly same content. How on earth would Google be able to figure that out? Let's say Google had 3 billion pages in it's database. To compare every page to every page would be an enormous task - quadrillions of comparisons.

Now, if site x had page "page1" which linked to site y which also had "page1", then it would be possible for Google to determine duplicate content. Conceivably, it could check this out.

Not only is task enormous, but benefit is so tiny as to be insignificant. Duplicate content does not imply in any way shape or form spamming. In actual fact, a duplicate site is generally going to lower page rank of BOTH sites. Instead of having 100 links to one site, there will presumably be 50 links to one and 50 to another. This would tend (all things being equal) to lower page ranking of both sites. So Google gains nothing by this incredible expenditure of resources.

There are several reasons for duplicate content which have nothing to do with spamming. Sometimes content is actually duplicated, and sometimes it's just that there are several different domains (at least www and non-www versions) for same website

Mirroring a site for load balancing - This is very common. The purpose is to split up traffic between two copies of site.

Mirroring for region - Sometimes site mirroring is done simply to make it more efficient on internet backbone itself. You might put an identical copy of a site in Europe, for example, to reduce traffic across Atlantic, which should make it faster in European countries.

Viral marketing - It's extremely common to allow other sites to republish articles in return for a link.