未查到Takedown notice的相关释义。可以先看一下notice and take down。

Notice and take down is a process operated by online hosts in response to court orders or allegations that content is illegal. Content is removed by the host following notice. Notice and take down is widely operated in relation to copyright infringement, as well as for libel and other illegal content. In United States and European Union law, notice and takedown is mandated as part of limited liability, or safe harbour, provisions for online hosts (see the Digital Millennium Copyright Act 1998 and the Electronic Commerce Directive 2000). As a condition for limited liability online hosts must expeditiously remove or disable access to content they host when they are notified of the alleged illegality. （Wikipedia）

（参考译文：通知并删除是指法院发出有关在线内容违法的命令后，网页寄存服务删除违规的在线内容。基本上很多涉及侵犯版权和诽谤的在线内容会走“通知并删除”这个流程。在美国和欧盟法律中，“通知并删除”是网页寄存服务的有限责任以及安全港条款的一部分（见1998年数字千年版权法和2000年电子商务指令）。网页寄存服务必须在接到有关存储的内容非法的通知后，迅速删除或禁止用户访问其托管的内容。）

如：

Under the "Notice and Takedown" system, upon receipt of a notice of alleged infringement from a copyright owner, an OSP is required to remove or disable access to material or activity identified to be infringing, and notify the subscriber who has been identified in connection with the alleged infringement of such removal or disabling.

根据"通知及移除"制度，服务提供者在接获版权拥有人发出的指称侵权通知后，须移除被指侵权的材料或终止接达被指侵权的材料或活动，以及就该项移除或终止接达向被识别为与指称侵权作为有关的用户发出通知。

笔者认为二者含义是一样的，供参考。