No, you won't! You decide what to share.
You and the person you invite to your plan, will indeed get full Premium access to the Blinkist library and features. However, you'll both get to keep your personal accounts separate, so that your personal library and activity will remain private.
You’re in full control; only titles you actively recommend to them or are recommended to you will be seen by the other person.
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For more information on how you can share recommendations with the other person, check this article.