Check with google webmaster tools. And also google will not show all the back links. If your link is in the internel pages , google not index the page. u will not get the link. in the case of directory and forum posting if the link in the inside pages google wont find ....
I actually know why this is - its so obvious, I found it out by experimenting and promoting many websites using various ways of linking, and one technique I used all the backlinks showed up in google, even on pages with no ranking !
there hasn't seem to been a wrong answer... I think Google updates their backlink system whenever it sees a backlink. this is how websites can be on the top 10 list within minutes.... Of course you will need to have that backlink come from a credible website Webmaster links updates itself every 1-2weeks. (From what I have seen) I have seen some of the links of mine...and I saw that the website had a 'nofollow' tag on it, but Google still placed it on my link list. The only way to find out is to verify it...and it's not hard to do.
As others have stated in the thread, the link: command only shows a portion of your backlinks as a way of protecting you. If your competitors were able to see what all backlinks you have, that google feels are important, then your competitors could simply go in and try to get backlinks from those same sources. Apparently in the past this used to happen. This is why you must verify your site in webmaster tools, and only then will google show you the links that they actually are aware of. I for one am glad that google does this. http://www.mattcutts.com/blog/google-provides-backlink-tool-for-site-owners/
If your backlinks update everytime PR is updated..then nobody will ever get to the top of search rankings. Google chooses to not show you as it maybe inconvenient to continually update us everytime it does something. It will also help them from not having us learning their secrets. Google chooses to not use the link: command because it waste their server's time with an inquiry. They consider this spam, and would prefer you to use Yahoo for this. (This was posted on a thread on DG) I can't find the exact thread but the poster posted the website in which a Google VP said this.
Google doesn't care to list all the backlinks because it reserves the right to choose the backlinks which it considers worthy. It displays approximately 10% of the total backlinks indexed by the Yahoo!
The answer is that google only counts unique links, so if your description is not unique then its seen as automated, or submitted en mass or possibly paid link, because all genuine links, genuine votes for a site are unique