Diigo website, web annotation, social bookmarking, highlighter, sticky notes, tags, outliner, groups, and research library

Diigo

Diigo is a web annotation and bookmarking website for saving online resources, highlighting web pages and PDFs, adding sticky notes, organizing research with tags and outlines, and sharing collections with groups.

Main website

diigo.com is the public website for Diigo's annotation, bookmarking, and research tools.

Core workflow

Users collect links, tag resources, highlight web pages and PDFs, add sticky notes, organize material with Outliner, and share research through groups.

Domain registered

December 22, 2004

Diigo official logo used as the brand image for the web annotation and bookmarking website.View Diigo logo

What Diigo is

Diigo official site presents Diigo as a website for better reading and research with annotation, highlighting, sticky notes, archiving, bookmarking, and organization tools. It is built for people who collect web resources and want those resources to remain searchable, annotated, and structured later. The Diigo Browser App Store listing shows current iPhone and iPad app access.

Collecting and tagging resources

Diigo's basic layer is bookmarking. A user saves a page, adds tags, and builds a personal library that can be searched later. Tags help a saved resource belong to more than one mental category, which is useful when one article might fit a class, project, client, research question, or writing idea at the same time.

Annotations and sticky notes

Diigo emphasizes annotation directly on web pages and PDFs. Highlights preserve selected text for later reference, while sticky notes can hold comments, reminders, questions, or short interpretations. That makes Diigo closer to a research workspace than a simple list of saved links.

Outliner and groups

The official site describes Outliner as a way to structure research from saved links, notes, and personal input. Diigo also supports groups for sharing research with classmates, colleagues, friends, or collaborators. In a classroom or team setting, this can turn scattered browsing into a shared source base.

Who uses Diigo

Diigo fits students, teachers, researchers, writers, knowledge workers, librarians, and teams that need to collect and discuss web sources. It is especially useful when the task is not only saving a page, but preserving why the page mattered and which passages were important.

Why it matters

The web is easy to search but hard to remember. Diigo matters because it gives readers a way to mark up sources as they read, then recover those marked sources later with context. Its value depends on the user's habits: bookmarks, tags, highlights, notes, and outlines need enough care to stay useful instead of becoming another pile of links.

WHOIS domain data

Data pulled: May 24, 2026View current WHOIS record

Domain: diigo.com
IP address: 54.148.192.94
Registrar: GoDaddy.com, LLC
WHOIS server: whois.godaddy.com
Referral URL: http://www.godaddy.com
Created: December 22, 2004
Updated: November 9, 2023
Expires: December 22, 2029
Nameservers: ns3.zoneedit.com (172.104.173.26); ns8.zoneedit.com (139.162.157.202); ns18.zoneedit.com (172.235.133.229)
Domain status: clientDeleteProhibited; clientRenewProhibited; clientTransferProhibited; clientUpdateProhibited

Key concepts

BookmarkA saved web page or online resource kept in a personal library for later retrieval.
HighlightA selected passage on a web page or PDF saved as part of the user's research context.
Sticky noteA comment or reminder attached to a page or passage.
OutlinerA structure for arranging links, annotations, and notes into a research outline.

Common workflows

Save a web page, tag it, and return to it from the personal library.
Highlight key passages while reading an article or PDF.
Add sticky notes to capture questions, comments, or reminders.
Share annotated resources with a class, project team, or research group.

Common misconceptions

Diigo is not only a bookmark list; its annotation, sticky note, group, and outliner features are central to the product.
Highlights are useful, but they do not replace careful source evaluation or note synthesis.
Archived pages and annotations can help preserve context, but users should still keep backups for important research.
The WHOIS record is domain registration metadata, not a full description of product ownership or operations.

Open questions

How can annotation tools make saved research easier to revisit without creating too much organization work?
Will AI-assisted summaries and tagging make web annotation more useful or less personal?
How should shared annotation groups manage moderation, source quality, and privacy?
What is the right balance between storing archived copies and respecting publishers' changing pages?