Mobile traffic anomaly investigation

Mobile traffic can fall while desktop holds steady, and the causes are specific enough to deserve their own procedure — mobile is judged against standards desktop is not.

The mobile-only causes

• The landing-page standard. A new interstitial, a floating bar, an advertising unit pushing content below half the first screen — any of these can restrict mobile display under Bingtong while desktop is unaffected.
• Permission walls. A login requirement, an app-install prompt or “open in app” gating content is prohibited on mobile. This is often introduced by a growth team with no knowledge of the rule.
• Adaptation broken. If the PC-to-mobile relationship stops validating — a URL structure change on either side — Baidu may stop substituting the mobile URL, and the two versions compete instead.
• The mobile spider blocked. A bot filter or CDN rule that admits the PC agent and rejects the mobile one produces exactly this pattern.
• Rendering resources blocked — CSS or JavaScript disallowed, so the mobile page is judged on a broken rendering.
• Handset-specific breakage after a release, including content obscured by system UI.

The diagnostic

1. Confirm the split: mobile down, desktop steady, in the platform data rather than in analytics alone.
2. Load a top landing page on a phone, from a search result, with no cookies. Measure the first screen. Try to read everything without logging in.
3. Check crawl diagnosis with the mobile spider on the same URL.
4. Check adaptation validation status.
5. Check for a platform message.

Why this pattern is common in international teams

Mobile growth features — app banners, registration gates, notification prompts — are usually owned by a product team working to conversion targets, not by whoever is responsible for search. In China those features are search violations rather than trade-offs, and the traffic effect appears weeks after the release that caused it.