When diagnosing an issue, you need to think back to what was the last item that changed. It could be a code push that somehow removed analytics from your site, it could have been a change to content that has caused a decline in search traffic. Did you make a change to your advertising? Sudden declines (or increases) are often traceable back to the last modification (big or small) that was made. - Greg Kihlstrom, Yes& Agency
The first thing to investigate after a major dip in traffic is your website itself. Is it actually working? Is there a problem with the domain? Mechanically, is everything functioning as it should? If all that checks out, make sure the critical inbound links are still intact. If the majority of your traffic comes from inbound campaigns, ensure your inbound marketing platform is working properly. - Jeffrey Kamikow, Cross Audience
It is crucial as your conversion rates will be greatly improved and the products and services you offer will be bought at a higher rate as you will be receiving the right kind of customers. In addition, the constant traffic that is channeled to your website will have a great role to play in lifting the ranking of your website thus providing you greater visibility in Google searches.
You may also want to use a third-party website for advertising purposes: with well-placed ads on blogs and websites that match your target audience, you reach many potential customers. In this context, it also makes sense to check website traffic beforehand, since the more people that visit your site means that more people come into contact with your ads.
Websites produce traffic rankings and statistics based on those people who access the sites while using their toolbars and other means of online measurements. The difficulty with this is that it does not look at the complete traffic picture for a site. Large sites usually hire the services of companies such as the Nielsen NetRatings or Quantcast, but their reports are available only by subscription.