You are reading a long article, a documentation page, a forum thread, or a research paper. You close the tab or the browser crashes you need to come back tomorrow. When you return, you have no idea where you left off. You scroll and scroll, trying to find that paragraph you were on.
Browser bookmarks only save the page, not the position. Reading-mode apps only work on articles. Annotations tools require accounts and sync your data to someone else's server.
Keep Sin solves this the simple way: left-click anywhere on a page, drop a marker or attach a note, and every marker is waiting for you the next time you open that page — right where you left it, at the exact paragraph, line, or sentence.
