Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Bookmark OS - Bookmark OS is like Mac or Windows optimized for bookmarks.
Planyway - Visual project management for Jira and Trello: manage resources, build project roadmaps, use time tracking.
BookmarkSheet - Your bookmarks in Google Sheets
Corrello - Dashboards for agile teams using Trello
Siimpl Bookmarking - Start collecting and organizing what interests you