Simplenote - The simplest way to keep notes. Light, clean, and free. Simplenote is now available for iOS, Android, Mac, and the web.
Brackets - A modern, open source text editor that understands web design
Google Keep - Capture notes, share them with others, and access them from your computer, phone or tablet. Free with a Google account.
Sublime Text - Sublime Text is a sophisticated text editor for code, html and prose - any kind of text file. You'll love the slick user interface and extraordinary features. Fully customizable with macros, and syntax highlighting for most major languages.
Coastline - Simple minimalist text editor. Create, open, edit and save plain text files.
Notepad++ - A free source code editor which supports several programming languages running under the MS Windows environment.