Cannot create a file with sudo in Apache web directory
sudo echo "" &gt; newfile should never have worked, because sudo only applies to the echo command and not to the redirection. Try using sudo touch newfile or echo "" | sudo tee newfile.

Sublime Text doesn't seem to support creating new files to a directory you don't have write permission to. It does support authenticating as root when modifying an existing file though. See http://sublimetext.userecho.com/topic/27820-prompt-if-need-elevated-permission-to-save/.

Maybe you did have write permission to the directory earlier but something (like upgrading to 10.9) removed it.