Here are three marketing and public relations techniques you could use, regardless of whether Google and other search engines exist.
1. Get Customers Involved in a Worthy Project
Notice how many successful brick-and-mortar retailers have a way of creating projects that give back to the community. At the same time they are also good at getting customers involved.
Macy's does a great job at this. Check out their list of projects from "Shop for a Cause" to "Back To The Books."
"Shop for a Cause" can be duplicated by any online retailer. To get the most link value, make sure to heavily promote your site's URL.
Next, modify the program to obtain even more links by getting your customers involved. Ask them to spread the word in social media and online.
Increase the results by asking if they have contacts in the media or with any bloggers. If it's a cause they are passionate about, they will help. Then watch the links start to develop.
2. Promotion: Customers who send New Customers
You never know who your customers are. Some will have their own website or blog.
With this in mind, run a promotion for those that send you new customers. An example would be giving them an electronic gift card to your store for each new customer they send who makes a purchase.
While many would run this only online for the links, your results can be increased by using offline techniques. A simple one would be to include 10 business cards with the promotion in each shipment. That way they can easily hand them to friends, co-workers, and family in their daily routine.
It's all about getting your customers to talk about you. Exposure equals links.
3. Engage Smaller Bloggers
Jeremy Bencken made an excellent point in "PR-SEO Mythbusting for Better Link Building":"Long tail blogs tend to be more receptive to personalized, relevant pitches (especially if you build a relationship with them first), and many of the top bloggers read smaller, upcoming bloggers to find and vet upcoming stories."
Many people tend to skip smaller sites thinking they don't have many backlinks so they won't count for much. But there are other reasons to engage smaller bloggers.
While these small blogs may not have the number of backlinks you're looking for, those backlinks might be very high-quality. Often that's going to be more valuable than a blog with thousands of low-quality links. You never know when those low-quality links will be further devalued in an algorithm change.
Another reason not to skip small blogs is some will turn into the influential bloggers as they develop a reputation and larger following. It's much easier to start developing a relationship when they're small. That relationship can be extremely valuable down the road.
By marketing your online retail store as if search engines don't exist, you can ensure your future success. Algorithms change and technology changes. What's important is you have marketing strategies that can adapt as well.