When marketing companies talk about websites, you may hear them say about traffic vs conversions. This basically means the number of visitors to your site versus the conversions (a conversion can be anything from an enquiry through to a sale online) and is vital in establishing how well your website is performing.
If you find that you are getting a lot of traffic through to the site, but not many of these are turning in to enquiries or sales, then you need to establish why that is. There are a number of points to look at when trying to work this out and often a large amount of testing will be needed to try and establish and fix the problem.
There is no point having a thousand visitors to your site every day but not having any conversions, so it is worth investing a proportion of your marketing budget in to investigating this and monitoring conversion rates.