First of all how the automated software works?,
Automated software scrapes the bookmarking sites from the net OR the user uploads a list to the software, it accept the sites based on the CMS platforms like pligg, scuttle, etc.
In the software accepted sites there will be lots of banned sites(Google have deindexed them), PR 0 sites, PR N/A sites, low quality sites!

That's why when you use a software, lots of links will be deleted within a month.Why?, those sites are hosted...