Netpadd can make backups of the current file, it has file sharing options within an intranet, it can display an (X)HTML document tree to validate the source. You can start a Java compile, call up a complete CSS syntax help. You can load files of any size. You have a code colorizer recognizing XML, XHTML, XSL, ASP, JSP, PHP.
There's a second clipboard. A jump to a line feature. Solid search, and search & replace, of course. You can convert characters to HTML, or look up special characters. You can see the output of an XSL transformation. You can convert tabs to spaces of your defined length. There's auto-completion features. You can easily wrap text with tags. Any many more things.