nofollow, sponsored and ugc on backlinks

The three values

The rel attribute on an <a> element describes the relationship between the linking page and the linked page. Google's documentation on qualifying outbound links defines three values that matter for backlinks:

A plain link with no rel value is one Google expects to fetch and parse without qualification. Google's page also says the values can be combined, as a space-separated list (rel="ugc nofollow") or a comma-separated one (rel="ugc,nofollow").

How Google treats them

According to the same documentation, links marked with these values will generally not be followed. Google adds two qualifications that matter for anyone reading a monitoring report:

• The linked page may still be discovered and crawled through other routes, such as sitemaps or links from other sites. A nofollow link does not hide the target.
• The values apply to crawlable <a> elements, except nofollow, which is also available as a robots meta tag covering the whole page.

The second point means a link can be effectively nofollow without carrying the attribute itself. A page with <meta name="robots" content="nofollow"> qualifies every link on it. Monitoring therefore needs to read the page head, not only the anchor, a point covered alongside other page-level rules on noindex and X-Robots-Tag.

Judging a rel value in monitoring

The second of the six backlink health checks compares the observed rel value with the expected one. The expected value depends on how the link was placed:

• Earned editorial links are usually expected to be plain. A later nofollow is a change worth noting.
• Disclosed paid placements should carry sponsored, which is Google's documented value for paid links. A sponsored value here is the healthy state, and its sudden removal could create a policy question rather than solve one.
• Community links in forums and comments are commonly ugc, often combined with nofollow. Google notes that sites may remove ugc from links posted by contributors with a consistent record of quality contributions, so such a change is possible but should not be assumed.

A monitor that flags every qualified link as a failure produces noise. It is more useful to record the value on each run and alert when it changes from the agreed baseline.

Why rel values change

Common reasons a link's rel value changes after publication:

• The publisher installed a plugin or theme setting that qualifies all outbound links.
• An editor reviewed sponsored content and added sponsored to bring it into line with Google's guidance.
• A forum or comment platform changed its defaults.
• A site migration rebuilt templates with different link handling.

These are among the "soft" changes discussed on lost backlinks. Unlike a deletion, they leave the link visible and clickable, which is why they are rarely spotted without ongoing backlink monitoring.

Practical reading of a report

The IndexChex monitor records rel values on each run, as do most link-tracking tools; check whether a given tool also reads the page-level meta robots tag. Glossary entries for rel="nofollow" and sponsored and ugc give the short definitions.