If you're an Internet marketer, you'll want to track your activity and gather it into statistics on a monthly basis at least. You cannot adjust your marketing plan or strategy if you don't know what's working, what's not working, and what the devilish details are--statistics tracking can certainly help you with this.
There are some statistics trackers that are free or very cheap, such as free hit counters; these are "off server" trackers, so their main advantage is in their pricing. However, off server trackers don't track with perfect accuracy, and they operate by "cumulative tracking", which is not as useful as monthly, weekly, or Date Range searchable tracking.
There is another class of off server trackers for which you must pay a decent amount. These work more accurately in exchange for the money you pay, of course. What's good about these is that when you move your hosting provisions they'll move with you. They also offer a more robust amount of tracking data--they aren't limited to the simple cumulative tracking which tells you nothing about the devilish details.
However, these might cost too much of your advertising budget if you are starting out or still small, and they still may not track as accurately as you desire.
Then there are the server side trackers. These are trackers that are on the same server as your website, and as a result your stats will be highly accurate, as these track all pages from all referral companies. You can use these to gather stat analyses on a monthly or weekly basis, and they'll give you date range statistics, too.
But keep in mind that the hosting company might charge you extra for this service. Also, if you change hosting companies you won't have access to the stats you had before the switch.
The first thing you want to pay attention to for your marketing purposes is the number of Unique Visitors that are coming to your site each month. If the same handful of people are hitting your site dozens of times a month that's not very effective or profitable for you unless they are buying from you every time (which they aren't).
Next, you want to see which other websites are referring prospects to your site.
If you have a load of links on other sites like article directories and standard listing ads, then you'll need to know if these sites show up on your logs as referrers. This is a big part of your tracking and will enable you to monitor which sites (on a free or paid basis) are directing traffic to your site. If the traffic from certain sites is substantial then you will want to keep a link on that site and possibly investigate if there is more you can do to improve click rates on the good ones.
The other way tracking is useful is in the way it gives you more information about what people searched for to find you. You can then analyze those keywords and optimise your web pages accordingly. For example, if someone typed in 'Silver gemstone Jewelry' on your 'jewelry site (if you had one) then you could go to google, type in this exact term and then see where you are placed in the search results. If you are getting visitors from appearing on page three, just imagine how many you could be getting if you were on page one for this term. You can then optimise that page and key term by getting more links into your site for that keyword.
If you are sure you have a hot product and a hot website but your statistics tracking shows you don't have the best traffic frequency, it means you need to change your marketing strategy and how you optimise the main landing pages of your site. If your conversion rate from 'landing to sale' is poor, you need to write more specific content which is both unique and interesting to the type of visitors that will order from you.