from Hacker News

This bookmarklet summarizes and reads text, listing the most context-relevant paragraphs first. The bookmarklet also changes text to aid visual processing and simultaneously speaks the text using the browser's text to speech function. The rate of speech can be varied by adjusting a slider at the top of the page.

The bookmarklet summarizes text by removing the most common English words from the source text and ordering the remaining words by frequency of appearance. Of these words, 10 context-relevant keywords are used to gauge the relevance of a given paragraph. The greater the number of keywords that appear in a given paragraph, the higher that paragraph ranks.