Domain strength refers to the overall value and authority of a website domain rather than individual pages. It can be measured using metrics like PageRank, Domain Authority, and the number/quality of inbound links. PageRank is assigned by Google on a scale from 0-10 based on incoming links, with higher scores indicating stronger domains. Domain Authority from Moz also uses links and other signals to predict search performance on a 0-100 scale. Strong, high-quality domains passing links to other sites help improve their domain strength rankings. Tools like the Google Toolbar and MozBar can help evaluate the domain strength of other sites.

1. Domain Strength

2. What is Domain Strength ?
Domain strength is the cumulative value of
an entire domain. Instead of looking at the
value of individual pages, we look at the
domain as a whole to understand how
strong it is.

3. Page Rank
 PageRank is calculated by Google and based on the number and quality of
links pointing to a web page.
 It runs on a scale from 0-10, with 10 being the highest.
 We can use the PageRank of a website's homepage to get an idea of how
strong it is.
 Although technically this is only the PageRank of a single page, it is still a
good indicator of the strength of a domain, because the majority of a
website's links will be to the homepage and PageRank flows from there to
internal pages.

4. Toolbar PageRank
 It should be noted that there is a difference between "Toolbar PageRank"
and the actual "PageRank“ used by Google.
 Toolbar PageRank is visible to you by installing the Google Toolbar on your
browser or by using a browser plugin/extension that pulls data from the
same source.
 It is updated every 3-4 months by Google, which is different from the
actual PageRank that is more fluid, constantly updated by Google to be
fed into their ranking algorithm.
 For that reason, the PageRank you see in the Google Toolbar could be
several months old. This is why new web pages mainly have a PageRank
score of 0: They need to wait for Google to update the toolbar.

5. Domain Authority
 Domain Authority is calculated by Moz and runs on a scale of 0-100, with
100 being the highest.
 It uses a number of signals taken from the Moz crawler and tries to
predict how well a domain will perform in search results.
 It is useful alongside PageRank as another indicator of how strong a
domain is.

6. Site Strength
 In terms of link building, site strength is a good metric to use because you
want to get links from websites that are very strong.
 If the links you get are from strong domains, they will pass more strength
to your own website.
 Which is a clear signal to Google that you have a good site that deserves
to rank well.

7. Example: CNN
 For example, CNN has a PageRank of 8 and a Domain Authority of 99.
 Lots of other websites link to CNN because it is an authoritative website
with high-quality content.
 Because of this, CNN is not very likely to link to low-quality websites, so if
you get a link from CNN, it is a signal that you have a good website, too.

8. Tools to Measuring Domain Strength
 PageRank extension for Chrome
 MozBar for measuring Domain Authority
 Google Toolbar for PageRank (for Internet Explorer)

9. Thank You
Rajat