AdBlocker Ultimate stores some data in your browser profile on your computer. AdBlocker Ultimate never transmits this data to any servers. Most of the data (your preferences, filter subscriptions and custom filters) is harmless privacy-wise. However, filter hit statistics and recent issue reports could be used to renovate your browsing history. AdBlocker Ultimate treats this information identically to how history data is treated by the browser: this data isn't stored if you are using Private Browsing mode and is removed if you choose to clear your browsing history.