Log4Classicning

OpenLayers 2.4 adds support for rendering vectors in the browser, using SVG in Mozilla/Firefox and Opera, and VML in Internet Explorer.
OpenLayers增加了浏览器中的矢量渲染功能，通过SVG在Mozilla/Opera浏览器中实现，而在IE中使用了VML技术。

The MouseDefaults and MouseToolbar controls have been deprecated, in favor of the new Navigation and NavToolbar? controls.
原本的MouseDefaults和MouseToolbar被弃用，转而代替的是Navigation和NavToolBar控件。

OpenLayers now implements a series of Handler classes that encapsulate common user interactions. Handler classes each implement a particular set of callbacks which are triggered on the relevant user interaction.
OpenLayers实现了一系列的Handler类封装常用的用户交互。

More on openlayers.org

早就听说了OpenLayers加入OSGeo后要有大改进，与MapBuilder合并之后OpenLayers将成为最重要的WebGIS浏览器端实现。