If your search query resembles a web address (URL), Google Blog Search automatically uses the link: operator and shows list of blogs that have earlier linked to the web address mentioned in your query.
Confused? Let’s see a simple example. If I search for labnol.org, Google Blog Search will auto-convert this query to link:labnol.org and show this resultset which is nothing but a list of web articles that are linking to labnol.org.
Today Google introduced some changes in the way they index content from blogs / RSS feeds.
Earlier they were only using links from RSS feeds to determine the resultset for link: operator but now they consider links that are mentioned on web pages as well very similar to Technorati.
This means that if another blog (abc.com) has linked to your own blog (my.com) from his sidebar, Google will now show abc.com in the results as well when you query for link:my.com.
If there were a Technorati Rank like parameter for Google Blogs Search, almost every blog may have seen major fluctuations in their rank due to this simple change.