The cheap cost of establishing an online store belies the true cost associated with generating a successful online business. This is something many advertisers omit to tell you when you sign up for "free" ecommerce packages - as with everything else in life, the only thing that is free is "free".
Establishing a website does not mean you will instantly attract traffic. A website has to be promoted to make itself more visible to people and who may then decide they are going to swing by for a visit.
The issue becomes, how do you drive traffic to your website in order to stand a shot at making some sales?

SEO Explained

The search engines are a primary means of control over who gets to see what on the internet. Most websites are found by gaining a high enough ranking in the search engines which means their listing gets read by more people and therefore, more traffic is generated as a consequence.
SEO (Search Engine Optimization) is the art of helping you become more visible to search engines, to gain a higher ranking and therefore improve your popularity.
How this is achieved will take a few volumes!

Create Original and Engaging Content

A crucial element for any website is engaging and relevant content. By content we mean the text, images, video, photographs, audio - everything your visitor will see and hear when they visit the site.

The greatest importance should be attached to the text you use, because this is the medium search engines work with (it's not easy for a computer program to categorize a photo or image unless the words are already associated with it). Search engines will categorize your website and ascribe a degree of relevance on a search term, used by a surfer, based largely on the words used on your site.
By creating relevant content which caters to the needs of your human readers, you will be more successful in making them stay or pay a return visit. Even better, you are more likely to be referred amongst other users too, especially amongst social media websites.

Using Social Media to Gain Wider Exposure - Going Viral

Social media sites cover a wide range of applications and websites in which the medium if exchange is personal information. Social networking sites such as Facebook and MySpace are two very good examples of social media sites, but there are quite literally hundreds of others which may cater for social networking or provide self-help and information services, e.g. Wikipedia.

In one respect, social media sites are an adjunct to the search engines as a means of sourcing visitors to your website. Surfers may use search engines for specific phrase searches but they are spending inordinate amounts of online time using social media sites.. There are two things you can do immediately - review the various social media sites which comprise the mainstream and establish your business pages on there and do some networking (this is free but time consuming). The second thing to do is to look for social media websites which cater for your particular product or service - if you are offering baby products, then look for parenting forums and sites or go into the larger sites and find the parenting groups - register on there and again, do some networking.

The Answer to the Question

The original question was if you build your website will the traffic come? The brutal answer is "No!" - building a website is like erecting a billboard in the desert, but online, this is a desert you can water and cultivate, and you can bring traffic to your door. Building your website is just one step on the road to creating a successful online business and for which you are going to need more than a simple website.