extension.harvard.edu
Link authority for extension.harvard.edu (registrable domain: harvard.edu) from the Common Crawl web graph: PageRank and harmonic centrality history since 2017, current scores, and the site's top backlink sources.
Web-graph authority (0-100)
Domain scores measure harvard.edu as a whole: every subdomain's links rolled up into one node of Common Crawl's domain-level web graph. Host scores measure the exact hostname extension.harvard.edu. WWW scores cover the www variant of that hostname, which the graph tracks as its own entry since January 2026 (before that, www and bare host were merged). A big gap between domain and host usually means the domain's authority lives on other subdomains. PageRank is link-endorsement authority: how much weight the sites linking here carry themselves. Harmonic centrality measures reach: how close this site sits to the rest of the web when following links, which favors broadly connected sites over ones boosted by a few heavy linkers. All are normalized 0 to 100 within each crawl snapshot; a dash means that series does not exist for this site.
Homepage
What extension.harvard.edu presents on its own homepage: the page title, description, and the social share markup it publishes. Pulled from https://extension.harvard.edu.
| Title | Harvard Extension School | Online Courses, Degrees, Certificates |
|---|---|
| Description | Take your career to the next level with a course or credential from Harvard. Online courses, master's and bachelor's degrees, and certificates. Start today. |
| OG Title | Harvard Extension School | Online Courses, Degrees, Certificates |
| OG Description | Take your career to the next level with a course or credential from Harvard. Online courses, master's and bachelor's degrees, and certificates. Start today. |
| OG Site Name | Harvard Extension School |
| Twitter Card | summary_large_image |
Social accounts and contact points
Where this site maintains a presence and every reachable route its homepage exposes: social accounts, contact pages, addresses, and content feeds.
| X | HarvardEXT |
|---|---|
| HarvardExtension | |
| Youtube | HarvardExtension |
| harvardextension | |
| harvard-university-extension-school (business) |
Structured data (JSON-LD)
The schema.org markup this homepage publishes: the machine-readable identity search engines and AI systems read. Types found: WebPage, BreadcrumbList, WebSite, Organization.
JSON-LD block (2,239 bytes)
{"@context":"https://schema.org","@graph":[{"@type":"WebPage","@id":"https://extension.harvard.edu/","url":"https://extension.harvard.edu/","name":"Harvard Extension School | Online Courses, Degrees, Certificates","isPartOf":{"@id":"https://extension.harvard.edu/#website"},"about":{"@id":"https://extension.harvard.edu/#organization"},"datePublished":"2025-07-21T13:02:08+00:00","dateModified":"2025-10-14T17:03:00+00:00","description":"Take your career to the next level with a course or credential from Harvard. Online courses, master's and bachelor's degrees, and certificates. Start today.","breadcrumb":{"@id":"https://extension.harvard.edu/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https://extension.harvard.edu/"]}]},{"@type":"BreadcrumbList","@id":"https://extension.harvard.edu/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home"}]},{"@type":"WebSite","@id":"https://extension.harvard.edu/#website","url":"https://extension.harvard.edu/","name":"Harvard Extension School","description":"Get ready for your next step","publisher":{"@id":"https://extension.harvard.edu/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://extension.harvard.edu/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https://extension.harvard.edu/#organization","name":"Harvard Extension School","url":"https://extension.harvard.edu/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https://extension.harvard.edu/#/schema/logo/image/","url":"https://extension.harvard.edu/wp-content/uploads/sites/8/2021/03/EXT_1-line_RGB_web_300px.png","contentUrl":"https://extension.harvard.edu/wp-content/uploads/sites/8/2021/03/EXT_1-line_RGB_web_300px.png","width":300,"height":57,"caption":"Harvard Extension School"},"image":{"@id":"https://extension.harvard.edu/#/schema/logo/image/"},"sameAs":["https://www.facebook.com/HarvardExtension","https://twitter.com/HarvardEXT","https://www.instagram.com/harvardextension/","https://www.linkedin.com/school/harvard-university-extension-school/","https://www.youtube.com/user/HarvardExtension"]}]}JSON-LD block (2 bytes)
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Authority over time
Every Common Crawl web-graph release since 2017, roughly quarterly. The domain series goes back to 2017; Common Crawl only began publishing the host-level graph in 2020, so host lines start there. Click a legend entry to show or hide that line. Flat lines are normal for established sites; watch for sustained rises or drops, which track real gains or losses in who links here.
A note on www: through the end of 2025 the source web graph merged www and non-www hostnames into the bare name, so one host line covers both. Starting in January 2026 the graph splits them into separate entries, which is why www can carry its own scores going forward.
Backlink counts
Unique linking domains seen in Common Crawl's link graphs. This is a different dataset than the 0-100 authority scores above: these are raw counts, host-level for extension.harvard.edu and domain-level for harvard.edu with all its subdomains combined. Common Crawl covers a large sample of the web, not all of it, so treat counts as comparable between sites rather than absolute totals.
Top backlinks in the domain graph
Common Crawl publishes two link graphs. The DOMAIN graph connects whole domains: every link from any page of one domain to any page of another. This table shows the highest-authority domains linking to harvard.edu (including its subdomains), ranked by the linker's PageRank. The table shows the top 1,000; the download carries the full stored list (up to 10,000 linkers) as JSON. Click a linker for its own site profile.
Top backlinks in the host graph
The HOST graph connects exact hostnames, so subdomains count separately. This table shows the highest-authority hosts linking to extension.harvard.edu specifically, ranked by the linker's PageRank. The table shows the top 1,000; the download carries the full stored list (up to 10,000 linkers) as JSON. Click a linker for its own site profile.