The goal of the Alpheios project is to help people learn how to learn languages as efficiently and enjoyably as possible, and in a way that best helps them understand their own literary heritage and culture, and the literary heritage and culture of other peoples throughout history. One of the principal tools, a Firefox plugin, allows a reader to browse a web page with Latin, ancient Greek, or Arabic, click on a word, and get a definition and morphological analysis of the word.

AnnotateIt lets users annotate anything anywhere on the web.

The Annotator's Workbench is a software tool that enables users to create a collection from a set of existing video files, segment that collection, create annotations and assign vocabulary terms to the segments, and control access. This tool is part of the Ethnographic Video for Institution and Analysis (EVIA) Digital Archive Project at Indiana University and the University of Michigan.

Annozilla allows you to view and create annotations associated with a web page. To use Annozilla you need to install the packages and get set up with an account with the W3C test server.

The purpose of ATLAS.ti is to help researchers uncover and systematically analyze complex phenomena hidden in text and multimedia data. The program provides tools that let the user locate, code, and annotate findings in primary data material, to weigh and evaluate their importance, and to visualize complex relations between them.

This online tool can be used for a wide variety of annotation tasks, including visualization and collaboration.

brat is designed in particular for structured annotation, where the notes are not freeform text but have a fixed form that can be automatically processed and "interpreted" by a computer. brat also supports the annotation of n-ary associations that can link together any number of other annotations participating in specific roles. brat also implements a number of features relying on natural language processing techniques to support human annotation efforts.

The Classical Text Editor was designed to enable scholars working on a critical edition or on a text with commentary or translation to prepare a camera-ready copy or electronic publication without bothering much about making up and page proofs. Its features, formed in continuous discussion with editors using the program, meet the practical needs of the scholar concerning text constitution, entries to different apparatus and updating them when the text has been changed, as well as creating and redefining sigla.

Co-ment is a text annotation and collaborative writing tool. Co-ment provides a friendly graphic user interface for text annotation, collaboration and writing texts online.

Commentpress is a theme and plugin for WordPress that enables granular public commenting on texts.