在當代資訊社會，包括個人資料在內的各種資訊乃決策所不可或缺， 資料蒐集者無疑地將有強烈動機蒐集個人資料。惟針對是否同意個人資料 被蒐集、利用或分享，當事人與資料蒐集者之間存在d資訊不對稱」。據此， 當個人不知何種資料被蒐集、如何被利用或分享、與因此將造成何種傷害 時，當事人將輕忽保持個人資料私密性的重要，極易導致同意陷阱之現象。 因此，關於個人資料的蒐集、利用或分享，應有「告知後同意」原則之適 用，當事人同意權的行使應以「被告知」與「自願的」爲前提，否則，個 人資料的交易實無自由選擇的空間。
告知後同意之首要，即在於使資料蒐集者蒐集、利用或分享個人資料 之實際狀況得以透明化，以利當事人同意權之行使。而「告知後同意」原 則主要包含「揭露」及「同意」二個面向爲主，資料蒐集者應以合理努力 使得當事人得以了解其個人資料將如何被蒐集、利用或分享；而同意應以 當事人對於其與資料蒐集者間之意思表示一致有所瞭解爲前提。
同意應符合下列四項標準才會在法律上生效：（一）同意必須清楚明確 地指出其意願;（二）同意必須出於自由意志;（三）同意目的必須特定;（四） 同意必須基於告知後所爲。我國並要求同意必須以書面爲之。再者，同意 不得有欺罔、誤導或錯誤之情事，否則，同意的效力將受影響。

In modern society, a variety of information, including personal information, is critical to decision-making process so that information collectors have strong motives to collect personal information. However, information asymmetries likely take place between data subjects and information collectors in deciding whether to consent to the collection, use or sharing of personal information. As a consequence, when data subjects fail to realize what kind of personal information will be collected, used or shared, and thus, the damages will be caused, they will ignore the importance of keeping personal information confidential. It will likely lead to the phenomenon of consent fallacy or consent trap. Therefore, the “informed consent” principle shall be applicable to the collection, use or sharing of personal information. The consent shall be informed and voluntary. Otherwise, there will be no room for making free choice in the market for personal information.
The key point of the “informed consent” principle is to make more transparent information collectors’ practices with respect to the collection, use, and sharing of personal information, which is helpful to data subjects’ decision-making. In fact, the “informed consent” principle includes two dimensions of disclosure and consent. Information collectors shall make a reasonable effort to inform data subjects of how personal information will be collected, used or shared. In addition, there shall be conditions for valid consent, namely: informed, clear, freely given, specific, and written. In addition, consent shall be not given under any of deceptive, misleading or unfair situations. Otherwise, the validity of consent will be affected.