Some new features in IE8 Beta 1:

  1. Activities – Activities are contextual services that provide quick access to external services from any webpage. Activities typically involve one of two types of actions.
  2. WebSlices – Web sites can expose portions of their page as a WebSlice that users can subscribe to and bring that content with them on their links bar wherever they are on the web. Users receive update notifications when the content changes.
  3. Choice of layout engine – Internet Explorer 8 Beta 1 will ship in standards mode by default. However, three different rendering modes (Quirks mode, Strict mode and IE8 standards mode) that may be set using the X-UA-Compatible header.

Copy + Paste from IE8 Official Site:

Internet Explorer 8 Beta 1 (Developer Preview)

Welcome to the website for Internet Explorer 8 Beta 1. Internet Explorer 8 Beta 1 is a developer preview for web designers and developers to help prepare their websites for the launch of Internet Explorer 8. Some of the new features designed for developers include a developer toolbar and improved interoperability and compatibility.

Internet Explorer 8 is designed to work in standard mode out of this box. However, Microsoft provides a way for users to browse the web in a way similar to Internet Explorer 7 by using the emulate Internet Explorer 7 button on the chrome. The web at your service

Internet Explorer 8 will take the web experience beyond the page. Internet Explorer 8 introduces a new way to seamlessly experience the best of the web whether you are a web developer writing to standards or a user discovering a new online service. Be one of the first developers to take advantage of improvements in Internet Explorer 8 for your websites and applications.

Official Site: Internet Explorer 8
Download: Internet Explorer 8 Beta 1