Semrush On-Page SEO Checker, and what an "idea" actually is

The word “idea” is doing a lot of work in this tool’s name, and it is the most honest thing about it.

These are not diagnoses. Almost everything the On-Page SEO Checker tells you is derived from what the current top ten results are doing, which means it describes a consensus rather than an opportunity. That is useful, and it is a different thing from a fault report.

It runs on keyword and URL pairs, and the source matters

Before it produces anything you have to tell it which page targets which keyword. There are four ways to do that and they are not equal.

Manual entry. Fine for one page.

CSV import. Fine if you already have a keyword map.

Google Search Console. The best option for pages that already get impressions, because it uses queries Google is genuinely showing you for, not queries you hoped for.

Semrush Organic Research. The best option for planning, and the one I’d pick. It pulls from real ranking data across the account.

Then it runs in bulk across all supplied pages at once. That bulk behaviour is the actual value: forty pages checked against their own target keywords in one pass is work you cannot do by hand.

Seven categories, and only some are tasks

Per page, the ideas arrive grouped. Reading them correctly matters more than reading all of them.

Semantic ideas. Terms the top ten use and you don’t. The most directly actionable category. Not a keyword-density exercise: usually it surfaces a subtopic you skipped entirely.

Content ideas. Length, readability, keyword placement. Mostly worth acting on, occasionally nonsense when it suggests matching the length of a page that ranks for other reasons.

Strategy ideas. Usually a polite way of saying your page targets the wrong intent. That’s a rewrite decision, not an edit, and it’s the most valuable thing on the list when it appears.

Technical ideas. Thin overlap with Site Audit. If you run both, Site Audit is the authority here.

SERP feature ideas. Whether the results page has a featured snippet or a People Also Ask block you could target. Genuinely useful and easy to miss.

Backlink ideas. A prospect list, not a task. It tells you who links to the pages beating you.

User experience ideas. Empty unless Google Analytics is connected. Connect it or ignore the category, but don’t assume the absence means you’re fine.

The lagging-signal problem

Worth being clear about, because it’s structural rather than a flaw to fix.

Everything derived from the top ten tells you what already works. Follow it faithfully and you produce a page that resembles the current winners, which is a reasonable way to reach position eight and a poor way to reach position one. Nothing in the recommendation set will ever suggest doing something none of the top ten does.

So the honest use is: run it to find what you omitted, not to find what to add. A missing subtopic is a real gap. A suggestion to hit 2,400 words because the average of the top ten is 2,400 words is a suggestion to be average.

Where it stops

This is a per-page tool, and treating it as a strategy is how people end up with a hundred pages of semantic suggestions and no ranking movement.

Run it on pages you have a specific reason to move: something at position 8 to 15 with real impressions in Search Console, or a commercial page that matters. Implement semantic and content ideas, read the strategy idea carefully, ignore the rest unless you have a reason.

Then the semantic and content ideas hand off to the content tools, which is where the actual editing happens.