User movements, behaviours, or preferences may be tracked and recorded  even when the app is not in use or settings are turned off. This is a  huge concern as aggregate data can reveal patterns or behaviours about  individuals and organizations, or state secrets from government  institutions. Aggregate data are valuable to third parties such as data  brokers and advertisers who sell the information, but also to threat  actors who can misuse the information for their cyber-attacks.

Some or all of the data may be transmitted through multiple  jurisdictions or stored on a server physically located in a foreign  country. If so, data may be subject to the laws of that jurisdiction  that could give lawful access to your data.

Data in transit or at rest may not be encrypted and is at risk of eavesdropping and tampering.

Many free apps or online services leverages the data they collect from  their user base to sell to third parties. Advertisers and other third  parties can use the information to develop targeted advertisements or communications that they sell to companies for marketing campaigns.

Data in transit or at rest may not be encrypted and is at risk of eavesdropping and tampering.

Anonymization is the process of removing or modifying PII (personally identifiable information) in collected data so it can no longer be linked to an individual. Anonymization can  be challenging to achieve completely as there may be remaining data  elements that can be used to re-create the original data, or cross  referenced with other data sources and potentially re-identify an  individual.