Modern word processors usually have built-in word counters. Even WordPress has it, keeping a running tally of words you type in. So what’s the big deal about tool?
It gives you a count of all the words on the webpage, not just the article you’ve posted on it, that’s the big deal.
Enter the URL of the webpage you want counted, and it gives you the total word count. As a bonus, it also gives you a ranked list of the words it found and each’s respective counts.
Likely just the way a search engine would see and evaluate that webpage. Or close to it. If you’re thinking SEO, then yeah, you’ve got the picture of why this free tool can prove invaluable.