I have submitted my website to directories,Forums and Social Bookmarking.Still I got only one backlink.
What would be the reason.

Thanks in Advance.

Have you checked if the links are no follow? also how long ago... the update only occurs every so often

You might also use Yahoo Site Explorer to check your backlinks:
https://siteexplorer.search.yahoo.com/

google search engine takes time to update their baklinks, it might take 15 days , so wait and watch , if u r using this forum to get sign baklinks then u r right , but its difficult to get backlinks frm free directories, social bookmarking sites can also be considered by search engines.......