10,000 years ago, when the inventor was the user, the feedback loop for design and usefulness was short and definitive. If the spearhead you made was hard to use, fragile, or ineffective, you found out quickly and the results might be deadly.
Today, specialization and the overall scale of our economy means that we don't often use, or even see others using, the things we design and create.

"Design" is far larger than most people's traditional notions of aesthetics and visuals. It is, essentially, about problem-solving and balancing constituent factors and objectives (including constraints) to produce an "elegant compromise" that, in the best case, is more than the sum of its parts.

People interact with web and mobile experiences in order to accomplish something meaningful. Keeping this in mind and considering context-of-use issues can help keep digital experiences focused and form a basic framework for designing and testing/vetting design.

People often talk about good design and bad design, but these are not very actionable or specific ways of measuring a digital experience's quality.
Since digital mediums are functional and people are there to do (or accomplish) something, it should be possible to measure UX quality more specifically.
Another deck of mine on HaikuDeck called "10 Measures of Good Design" covers this topic in more detail.

There are many definitions of innovation, and my attempt to define it here is not meant to supersede all others. It is merely a way to frame innovation in the context of UCD.

Saying that your product is innovative (sometimes even before you've designed it!) is like starting a joke with "Hey listen, this is really funny."
Innovation exists purely in the minds of your customers. If it was possible to be innovative 100% of the time, the stock market would look far different than it does today.

Relevant simply means solving an actual problem in your customers real lives. And the concept of "net" is also key here.

Think of the value your product provides as a vertical bar. The higher the bar, the more real value. But that bar is reduced in height by effort, confusion and friction, sometimes to the point that the net value is not positive.
Products that provide a lot of value with minimal effort and confusion get described as "intuitive" and "magical". It's a bit like a value perpetual motion machine - you get more out of it than you put in.

Two points here.
1. Features compete with one another for your users' attention, and too many features can destroy the value.
2. A particular feature ALWAYS has an opportunity cost in terms of taking up space and attention, but only SOME features are valuable. This makes features very risky to deploy in your experience, as they can quickly add up to net-negative experience if there are too many with little value.

Innovation is not a function of ego or a path to bragging rights. It's about the value it provides to real people.
Consider that piece of plastic at the end of your shoelace - the "aglet". Problem-solving, game-changing, but it would never qualify as a "shiny object" on someone's roadmap.

Sometimes, innovation is truly "net new", but it doesn't have to be. Many innovations are improvements to things that people already do and expect to be able to do.
And if you aren't already nailing what they are there to do in the first place, you probably won't get a chance to wow them with something brand new.

Gathering lots of user-centered data is critical, but no single source is the Truth with a capital "T". Design decisions require skill and nuance, and having experience with digital research methodologies and their ins and outs is paramount.

Asking customers what they think or like is fine, but watching them use your product is better. People have been proven to be unreliable in reporting their own behavior, even immediately after the fact.

If you design your product based on solid notions of what your customers value and then test it against those same tasks and look for high levels of successful completion, confidence and brand impressions that align with who you want to "be" in their eyes, you will have a best-of-breed product.
That doesn't mean, however, that it will meet your own pre-formed opinions or cover every angle you originally cooked up.
Be diligent about methodology, of course, but trust the output when it's done right.

An increasingly challenging problem in our digital world is how to retain the humanity of customer service and experiences?
Human Parity is powerful design filter to use on all of your digital products - Does your digital experience behave in ways that you wouldn't allow a person representing your brand to act? Is the experience of your web site, mobile app or any of its features or components something that would get a real live employee fired if they did the same (or analogous) thing to a customer?
Sadly, the answer is "yes" more often than it should be, but why? Digital experiences are the way that more and more customers will experience a brand, and we must strive to make those experiences as good, or better, than what we would expect from someone wearing a uniform or logo-shirt.