New back-links towards my website that are indexed by Google appear every day, but the number of links is not updated by Google at all, it remains constant and this has been going on for about 1 year now. At link-back.net which practically takes the Google’s query result “link:mysite†and compares it with the previous result, I can see every new links, each day there are 1-2 new links but still the number of indexed links is unchanged…it’s the same as a year ago.
Google does update BL periodicaly and don't show any more real data. It just shows sample of data (small percent). Yahoo's siteexplorer shows better backlinks. Or you could use webmaster tools here to check. You got more information.