Direct answer
If you’re diagnosing or configuring a VPN to understand online tracking, the main risks and limitations are that a VPN does not guarantee anonymity, safety, or access, and it cannot stop every tracking method. Even when traffic is routed differently, websites and apps may still identify you through cookies, logins, device/application identifiers, fingerprinting signals, or other account-linked data. Also, VPN performance and availability can vary significantly with your network, device, location, provider, and time.
How it works in practical terms
A VPN typically creates an encrypted tunnel between your device and the VPN endpoint, changing what local networks and some intermediaries can see. In an online tracking context, that means observers who rely on your direct IP address may see the VPN endpoint’s address instead. However, online tracking is broader than IP visibility: it also depends on what a site/app receives (and records) after the connection is established, plus any identifiers already stored or shared.
Practical context, possible consequences, and control points
Common scenario: you test tracking behavior (ads, personalization, login prompts) after enabling a VPN. A key limitation is that “less tracking” on one dimension does not mean tracking is gone overall. Possible consequences include continued personalization because you remain logged in, cookies persist across sessions, or app telemetry still flows through identifiable endpoints. Control points include isolating variables (browser vs app, logged-in vs logged-out), clearing or using separate profiles when appropriate, and checking whether the tracking change you observe is consistent over time.
Limitations to keep in mind
Performance and reach can fluctuate, and a VPN may not work the same way across networks or geographies. Additionally, some legal and policy constraints can affect what you can access or how services respond. Finally, any current performance, feature, or legal claim about a specific VPN product should be treated as needing up-to-date verification.