Estimate your site's health by reading the wrong metrics and you get the wrong impression.
It's as simple as that.
Whether it is for setting a price for on-site advertising or establishing some kind of baseline when negotiating SEO or SEM services, traffic measured in absolutes such as Page Views, Visitors and Unique Visitors has a hold on The Market it really doesn't deserve.
Technology has surpassed most of these metrics.
Think about it.
You might be reading this in your feed reader. Are you a Unique Visitor? Does the Page View get increased somewhere? Or maybe you're subscribed by email: same questions apply.
But hey, no, you're a "regular" web visitor, you say, so +1 Unique Visitor and +1 Page View. But are you? Maybe you're browsing this from work on the office machine, bookmark the site and come back here in the evening from your home desktop computer. Start reading something interesting, grab the laptop and continue reading in the living room. Heck, for all I know you have a web enabled mobile device!
What happens to those visits? +1 Unique Visitor for each? +1 Page View for each?
If you want to muddle the data pool even more, add "widgets" or "gadgets" to it. How do you measure those? Think Flash interface or AJAX technology.
All together it means that absolute traffic statistics are off, way off, and in many cases present at best a partial look at how well a site is doing. Web traffic is on the way out.
Measurable Goals
It is tempting to replace absolute traffic numbers with measurable goals. Number of subscribers to a feed. Number of subscribers to a newsletter. Conversion rate.
In my opinion these suffer from the same problems. Conversion rate is measured against web traffic, for example. The absolute number of subscribers to a feed differs from day to day and doesn't take any caching into account.
I think the problem is thinking in The Absolute Numbers
Measurable Trends
One thing that remains the same is that you have to grow. From $10/day to $100/day. From 1 subscriber to 100 subscribers.
But instead of measuring this as absolutes, use tools such as Google Analytics' "compare" to see what your trend is.
Is your trend going upwards or downwards? Are you growing or shrinking?
I don't think measuring trends stops there though. When is the last time you checked what the buzz around your brand or site was among people who blog and thus influence wide and narrow audience? Since introducing your latest price cut, how many times have people posted about it on forums? Have you setup a mechanism to measure how many times your emails get forwarded? What did your last customer satisfaction survey say? Has your customer service response time gone down? How engaged are your visitors? How thrilled?
As web technology changes and grows, so should our measurements.