PAGE LOAD SPEED
How quickly your pages load is important no matter what function the site serves, but ecommerce sites are a place where the problem often occurs. Shopping online is a very visual process; even eBooks and MP3 downloads, which we never even hold a physical copy of, feature cover art on their product pages.
While many products may only require an image or two, there are times when a retailer will go overboard, adding image after image in an effort to more fully show a product. Multiple images can be used without negatively affecting page load speed, if the proper care is taken.
Large images that allow users to zoom and see a product in great detail can be great for certain things, but if used in great numbers (or if the images are waaay too big) it won't be long before certain pages of your site are loading slowly.
Slow page load speeds are never ideal. With the abundance of information on the web today, visitors have less and less patience when it comes to getting what they want; even a few seconds can be enough to cause a potential customer to bounce and buy the same product elsewhere.
Even search engines like Google look at page load speed. Google prides itself on speed, as is evident by the note at the top of every search page, "About xxx,000 results (0.xx seconds)," but they know that it goes further than how fast they return results to their users. At the basis of every update Google releases is an effort to return better results. The way they see it, if a site is slow it's not going to provide visitors with the information they need or the experience they want. As they said themselves, "Faster sites create happy users [...] Like us, our users place a lot of value in speed."
There are other problem areas to look out for in addition to product pages. Categories pages and galleries, for example, can be problem areas. Filling categories and galleries with too many items without the proper use of pagination will overwhelm browsers and slow down load speeds and response times. Be careful about how much you're trying to display at once and remember, people don't always mind clicking.
Most newer sites don't have to worry about speed issues, as it's often taken into account during the construction of the site, but it's always smart to visit your own site and be aware of how it's working. When fairly simple changes can go a long way in improving rank results (for sites that already suffer from slow loads speeds) there's no reason not to dedicate some time and money to them.
Product descriptions are essential for ecommerce. When a customer is physically shopping, the simple acts of holding a product and reading a tag can make all the difference between one purchase or another. Combined with images, they provide the basis for any online purchase and a shortage of (or inaccessible) info can hurt sales. (I once bought what I thought was going to be a messenger bag big enough to fit my 15" laptop. It wasn't made clear that the dimensions were in centimeters, so I ended up something more like a purse.)
Unfortunately, the mere existence of product descriptions isn't everything. Many online retailers resell products from larger companies, and oftentimes a stock description accompanies each product. It may seem easy and convenient to have those pesky product descriptions provided to you, but there are unintended, and often unconsidered consequences.
It all comes down to duplicate content. When a search engine like Google displays search results, it attempts to display distinct pages with distinct content for their users. When it encounters duplicate content across the web, Google does its best to determine which site is the origin of the content. If multiple other sites feature the same content you do, it's more than likely that you're not going to rank well (if at all) for those products.
It's more work, sure, but taking some extra time to craft new content for your products will help ensure that new customers can find you via search engine results. When compared to the alternative of not being found at all, that's well worth the hassle.
Customer reviews are trickier, because you aren't in control of them yourself, but they're just as valuable (if not more in some cases) than the content you craft yourself. Reviews give your customers the ability to post about their experiences buying through you and using your products. Now, it can seem scary to give such site real-estate to people who don't have to write positive reviews, but if you're doing your job right do you really have any reason to worry? If all of your customers are coming away unhappy, you have bigger problems that need figuring out...
As with product descriptions, reviews provide potential customers with an added level of information about what they're going to be purchasing. The more information consumers can find on your site (whether it's through descriptions or reviews) the more likely they are to buy it from you. Inversely, if someone has to leave your site to find more information you've likely lost them for good... and not just for this sale.
Not surprisingly, these customer reviews are great for SEO too. Not only do they serve as a vehicle for new content (and possibly keywords too!), but they are continually gaining more and more usage in search results.
The one major mistake is to not offer the ability to write reviews. Granted, not every site needs them featured as prominently as Amazon. If you sell a unique product that people aren't going to find elsewhere, there isn't as much pressure, though credibility indicators like testimonials are always a good idea.
For those retailers that resell another company's products (or sell a product for which many different brands/stores exist), customer reviews are hugely important. Good or bad, reviews attract attention from search engines, and with 88% of people reading customer feedback when making a purchase, can you afford not to have them?
Traffic isn't everything for ecommerce sites, but it's the first thing; users need to convert too if a business is going to succeed. In this day and age, however, the prevalence of search engines dictates that certain steps need to be taken to capture that traffic. Sure, an ecommerce site with slow page load speeds, lacking or duplicate product descriptions, and no customer reviews can still sell products, but by taking the time to improve these areas you can better optimize your site to rank better and let the search engines help you be found.