Free Tools For Getting Your Backlinks Noticed by Search Engines
A backlink can only be counted towards your website pagerank if that link is dofollow and if the search engine knows of the website you got your link from.
PING:
You can ping the web page using free ping services such as PINGLER and PINGOAT.
RSS SUBMISSIONS:
You can submit their websites to RSS submission services. You can use HostMyRSS to host those RSS feeds for free.
