TabNote is described as 'use your Browser as your Notepad, take notes while you are browsing' and is an app in the Office & Productivity category. There are more than 100 alternatives to TabNote for a variety of platforms, including Windows, Mac, Linux, BSD and Online / Web-based. The best alternative is Notepad++, which is both free and Open Source. Other great apps like TabNote are Atom (Free, Open Source), Sublime Text (Free Personal), Vim (Free, Open Source) and gedit (Free, Open Source).
GNU nano is a small and friendly text editor. Besides basic text editing, nano offers many extra features like an interactive search and replace, go to line and column number, auto-indentation, feature toggles, internationalization support, and filename tab completion.
The Kate project develops two main products: KatePart, the advanced editor component which is used in numerous KDE applications requiring a text editing component, and Kate, a MDI text editor application.
Bluefish is a powerful editor targeted towards programmers and webdesigners, with many options to write websites, scripts and programming code. Bluefish supports many programming and markup languages, and it focuses on editing dynamic and interactive websites.
CudaText is a cross-platform text editor, written in Lazarus. It starts quite fast (0.5 sec with ~30 plugins on CPU Intel Core i3 3Hz). It is extensible by Python add-ons (plugins, linters, code tree parsers, external tools).