If someone uses your site, app, or service for a year, reward them, celebrate them, thank them. It's one of the simplest ways to improve your relationship with your customers and few companies do it.
I actually can't think of a single company I frequent that acknowledges ongoing loyalty, outside of displaying “Member since” on an account page or membership card. The Internet makes it trivial to switch companies, which makes it incredibly rare that someone remains a customer or member of a site year after year. These are likely your most valuable customers. Why not do everything you can to reward and keep them?
The bar is so low that a short, thoughtful email from the CEO each year (which could be written, designed, and automated in a day or two) would put you in the top 5% of companies.
I just wanted to thank you for being a customer. You made your first purchase with us one year ago today and a few more since. We hope we've exceeded your expectations each time. If we haven't, please let us know so we can improve. We look forward to working with you for many years to come.
That's it, really. Acknowledge the milestone, show appreciation, and provide an easy way to respond with questions or concerns (and then address them, obviously). Another option would be a note inside the site itself. The more personal you can be, the better. If you're small enough, you could sign and mail an actual note.
Rewards are certainly an option, too, such as a discount on the next order, free shipping, or maybe early access to a new feature or high-demand product. The free birthday drink that Starbucks gives to card holders is a good example of this - simple, no fine print, and more personal than most large corporations tend to be.
Subscriptions are a little different. We often use pricing to encourage loyalty through the early-bird approach; be one of the first to sign up at the temporary, lower rate, then keep that rate as long as you remain a customer. That works well for your very first customers, but what about the many more who sign up later? What if the subscription price actually decreased each year someone renewed, or the benefits increased? It's an idea I'd like to experiment with for Uncommon eventually.
Companies are typically good at recognizing and rewarding dedication when it comes to employees. Start date anniversaries are acknowledged, sometimes celebrated, and loyalty rewarded through increases in salary, perks, and vacation days. A similar approach can show your customers that they are valued.
We have all of these fields in our databases for a reason. Find your loyal customers and treat them with the respect they deserve. It's simple, right and, in the end, smart.