Authority is a measure of popularity - how many blogs link to another blog. 

 

There's this common thing called "Technorati Authority". 

 

Technorati Authority is determined by the number of unique blogs [which are indexed by Technorati] that have linked to a blog in the past 180 days and the number of links which appear in a blog's Blog Reactions.

 

As links from blogs age out of this window and new links are added, your authority may rise, fall, or stay the same over time.

 

If the same blog links to a blog many times in the past 180 days, it only counts once towards Authority

 

The higher the number, the more Technorati Authority the blog has.

 

Checkout the Technorati Rank.