If you compare websites for research or outreach, you need to know which entity and period each link measurement describes. Link Graph: Site shows monthly PageRank observations for a registrable domain, a requested host, and its www variant where those records exist. Link Graph: Multi-Site compares several sites.
Choose the entity before comparing values
A domain can include a main site, a shop and a publication on separate hosts. Domain values and host values describe different collections of links, so compare the same level across the sites you are reviewing.
The www host also has a separate record. A change in host representation can produce a change in the chart without an equivalent change in the business.
The www change of January 2026
That last point has one specific and common cause worth knowing before you read any chart.
From January 2026 the underlying graph began counting www.example.com separately from example.com. For sites serving from the www hostname, the bare host's figure drops close to nothing from that month and the www figure increases.
The worked example is an anonymized host: host 56 and www 0 through December 2025, then host 31 and www 56 from January 2026 onward. Nothing happened to that website.
The chart uses the bare host before January 2026 and the www host from that month onward to show one line for the site. Apply the same rule when analyzing exported rows. Otherwise, www-served sites will appear to have declined sharply in that month.
Read the dates and the missing observations
Observations run from 2017 in the collection, and charts are drawn from January 2020, so the record can be deeper than the chart shows.
Coverage varies by site and by graph level. A missing month or an absent host record is not a measured zero, and treating it as one produces a dip that never happened.
Batch limits
Multi-Site accepts up to 100 hostnames. A longer list is refused outright with both counts named, and nothing in it is looked up. The refusal is complete on purpose: a partial answer would return the first hundred and leave the rest to be noticed.
Use the sequence to decide what to investigate
The shape matters more than the current value. A site holding steady, one climbing for two years, and one that peaked in 2022 can all show the same figure this month, and they are three different prospects.
Inspect the current content and the referring sites before attributing a movement to lost links, a migration or a change in publishing activity. The chart identifies a question rather than answering it.
What PageRank here is not
It describes the collected link graph. It is not traffic, not topical relevance, and not a measurement supplied by Google about that website.
It is comparable within this dataset, between sites and against a site's own past. It is not comparable with a figure from any other dataset.
When recording a site comparison, keep its domain or host level and observation dates with the values you use.
See PageRank and PRoT, how the measurements are produced, or checking a prospect before outreach.