Picture this: you've spent months getting your Shopping campaigns to a place you're happy with. Budgets capped, ROAS holding, cost per sale where you want it. Then Google quietly changes how the bidding maths works, and suddenly the campaigns that were behaving themselves start spending more to chase a target you set eighteen months ago. Sound familiar? That's the change landing on 17 August, and it's the biggest thing in this week's news for anyone selling online.

Here's what's happening across Google Ads and AI search this week, and what it actually means for your business.

Google's Target-Based Bidding Change: Read This One Twice

This is the headline. From 17 August, Google is changing how budget-limited Target CPA and Target ROAS campaigns behave. Right now, if your campaign is capped by budget, the system effectively works within that constraint. After the update, Google will push those campaigns harder toward hitting the target you've set — which, in plain English, means they may spend more.

The full detail is here, but let me translate it into what matters for your P&L.

If you set a Target ROAS of 400% a year ago and then quietly capped the budget because the campaign was overspending, you've been running a hybrid setup: a target on paper, a budget doing the actual work. After 17 August, the target starts doing the work properly. If that target is loose — say you set 300% back when margins were different — Google now has permission to buy a lot more traffic at 300% than your budget cap was previously allowing.

What this means for you: go and look at every Target CPA and Target ROAS campaign that's currently budget-limited. Not just the big ones. Ask two questions of each: is this target still the right number for my margins today, and would I actually be happy if this campaign spent 40% more at that target? If the answer to either is no, the time to fix it is now, not in September when the invoice arrives.

Budget-limited campaigns with stale targets are the ones I'd audit first. It's a five-minute check per campaign and it's the difference between a controlled change and a nasty surprise.

Google's AI Report: People Are Using Gemini for Real Decisions

Google published an AI & Economy report comparing how people use Gemini and AI Mode against how they actually spend their days. It's the kind of thing that looks like PR fluff until you read what's in it — it's worth a look.

The interesting bit for e-commerce isn't the raw numbers. It's the confirmation that AI conversations are becoming a genuine research step in buying decisions, not a novelty. Someone deciding between two garden furniture sets or two laptop models is increasingly having that conversation with an AI before they ever type a query into a search box.

What this means for you: the traffic that eventually lands on your site is arriving with more of the decision already made. That changes what your landing pages need to do. Less convincing, more confirming. If your product pages are built to sell from cold, they may be doing the wrong job for a visitor who's already been briefed by an AI and is just checking the price and delivery date.

The robots.txt Trap That Can Quietly Break Your Site

A more technical one, but it matters. Google's John Mueller explained a quirk where Googlebot can end up ignoring your robots.txt rules entirely.

For those who don't live in this world: robots.txt is a small text file that tells search engines which parts of your site they can and can't crawl. Most e-commerce sites use it to block things like internal search results, filtered category pages, and checkout URLs — pages that would otherwise flood Google with thousands of near-identical URLs.

The quirk is that if the file can't be fetched reliably, or the setup is wrong, Google may just disregard it. And if it disregards it on a big Shopify or WooCommerce store with faceted navigation, you can suddenly have Google crawling tens of thousands of filter combinations it was never meant to see.

What this means for you: if your organic traffic has moved oddly, or your Search Console coverage report has grown a strange tail of indexed URLs you don't recognise, this is worth checking. It's a small file that does a big job.

What Does AI Say About Your Business? Go and Ask It

There was a good session on auditing what ChatGPT and AI Overviews actually say about your business and locations — the recap is here.

This is genuinely one of the simplest, most useful things you can do this month, and it costs nothing. Open ChatGPT. Ask it about your brand. Ask it what your delivery times are, where you're based, what you sell, whether you're any good. Then do the same in Google's AI Overviews.

You will almost certainly find something wrong. Old opening hours. A discontinued product line. A delivery promise from three years ago. Possibly a competitor mentioned in the same breath as you.

What this means for you: AI systems are answering questions about your business right now, whether or not you've thought about it. Those answers come from your website, your Google Business Profile, your reviews, and whatever else has been scraped along the way. If the inputs are stale, the answers are stale — and unlike a bad Google ranking, you can't outbid your way past it.

Publishers Are Wobbling and Search Growth Is Slowing

Finally, a bigger-picture one. This week brought a court dismissing Google's DMCA claims against SerpApi, an €890 million EU fine, major publishers openly weighing whether to leave Google, and evidence that Search growth is easing. The full round-up is here.

None of this changes what you do on Monday morning. But it's the backdrop to everything else in this post. Google is under legal pressure, growth is flattening, and the AI products are where the attention is going.

What this means for you: the platform you're advertising on is changing shape. Not collapsing — Search still sends the vast majority of commercial traffic — but the certainty that Google is the only game in town is softening. Which is exactly why I'd rather clients spend a bit of energy this year making their product data, their site content, and their brand information genuinely good, rather than purely optimising for one channel's algorithm. Good data travels. It works in Shopping, it works in AI answers, it works wherever the traffic comes from next.

What to Watch

The 17 August bidding change is the one with a date on it, and it's the one that touches your bank balance directly. Audit your budget-limited campaigns before then — targets, budgets, and whether you'd be comfortable with more spend at the current target.

Everything else is slower-moving but pointing the same direction: the systems deciding whether your products get shown are increasingly reading your data, not just your bids. Getting that data right is the work that pays off in every channel at once.

I'll be watching how the bidding update behaves in the wild once it lands, and I'll report back on what actually happens versus what Google says will happen. They're not always the same thing.