I feel the most unreliable measurement is someone telling me they liked the website.
I prefer starting with the concrete measurements: traffic analysis and newsletter signups.
Google Analytics is my main tool for traffic analysis. It gives me a good overview of what who is visiting my site, how often and what content is looked at most.
I also have access to the raw traffic logs which I use a log analyser to give me more accurate and specific information.
The other measurement I use is newsletter signups. My newsletter signups answer the question: Is my content useful enough that people will choose to receive yet another email every month?
Starting with these two items, I can begin measuring the usefulness of the site. How many page views did I get this month vs. last month? Are my newsletter signups growing steadily? How many unsubscribes am I getting?
If something isn't working like I think it should then I can make changes. For example, I have expected path that I think a visitor will take going through this site. If they're clicking on something that I don't expect, I'll see that in my traffic logs and I can make appropriate design changes to lead visitors to the content I want them to see first.
Measuring is an ongoing process. It lets me know if I getting closer to the desired results of this web site.
How do you increase sales with an already profitable company?
Answer: Expand your client-base to a market segment with more disposable income.
How do you make your favorite hobby even better?
Answer: By getting someone else to pay for it.
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