And our measurement tools are proving that those ads are working better and better. So I’m confident that we’ll — as the demand picture normalizes, we’ll see some upside from a revenue perspective. But we also know that there’s another part of this equation that’s on the cost side. And from a gross margin perspective, you saw in this current quarter that our cost of revenue declined quarter-over-quarter after meaningful expansion through the year. That’s a product of more discipline from an infrastructure standpoint and hope to continue to invest in further optimizations through the year, which creates a little bit more headroom for OpEx. And as Bill mentioned, we slowed hiring pretty significantly in the summer of last year. We took some actions in the fourth quarter.
We’ve taken more actions already, and we continue to evaluate other levers, including things like our real estate portfolio, to make sure we’re on track to deliver that margin expansion. If I’m in your shoes thinking about modeling how the year will unfold, you probably can sense from my guide that year-over-year OpEx growth for the first quarter is a huge step down from the year-over-year growth that we posted in the fourth quarter on OpEx. You’ll see another meaningful step down and further step down as the year unfolds because we’re lapping in each of the four quarters because we’re lapping a lot of headcount-related investments that we made in the first half of last year. And then we’re lapping a lot of our brand and marketing campaigns in the back half of the year, including some creator rewards programs, which we would dial back and are discretionary.
When you think about that from a modeling perspective, that means that we would be able to post much, much, much reduced OpEx growth through the course of the year that should support even low levels of revenue growth, driving margin expansion. Operator, next question.
Operator: Thank you, Mr. Sandler. The next question is from Brian Nowak with Morgan Stanley. Please proceed.
Brian Nowak: Thanks for taking my questions. I have two. The first one, you’ve made a lot of progress around users and sessions and engagement. I was just wondering if you have any stats to share at all about clicks to advertisers, interaction with advertisers or anything on transaction? I know it’s early, but just any way you can quantify sort of some of the early progress you’re making on your users engaging more with your advertisers? And the second one, Bill, I guess, if you sort of look at your user behavior as well as the key merchants and inventory you’re putting on the platform, what are sort of two or three of the most important verticals in e-commerce that you think are going to really catalyze the advertising growth to materially faster growth over the course of the year into next year? Thanks.
Bill Ready: Maybe on the first question, on the progress we’re seeing there, I mentioned in my remarks, shopping ad is growing 50% year-on-year as well as not only solving for shopping, but giving easier conversions, easier ability for the user to connect with the place to buy through our mobile deep linking capabilities. And so I shared how significant the percentage of revenue from shopping apps is coming from mobile deep linking. I think that is an early indicator of just how much we can do not only to make more of our content shoppable, but also our ability to drive that full funnel engagement where we’ve historically been much stronger at the upper and mid-funnel. But at the lower end of that funnel, we’re seeing that low-funnel conversion objective being about a third of our revenue overall in things like mobile deep linking, which we have not had that adopted across the board, but the early adopters of that have seen really strong performance.
