If you want to change the behavior of when you past content into the Sitecore Rich Text Editor, you can change the settings used by the Telerik control.

This is embedded into the application via:

/sitecore/shell/Controls/Rich Text Editor/EditorPage.aspx

Then the attribute that causes the change in behavior is:

<telerik:RadEditor ID=”Editor” Runat=”server”
…
StripFormattingOnPaste=”All,ConvertWordLists”

…

To see all options for the enumeration, have a look at http://demos.telerik.com/aspnet-ajax/editor/examples/cleaningwordformatting/defaultcs.aspx