What's the URL in question? If you know the site has 30K backlinks, you can easily see where those backlinks are coming from and duplicate the process if you so choose. Directory submissions are only one link building method, and I doubt they make up any signficiant part of the 30K backlink profile. If many of the backlinks are from web directories, chances are there are many sitewide links. If you write some good articles/posts, you may pick up some good links through rss feeds. Have some of your own blogs or directories? Place a link on them and get thousands of backlinks to point to any URL you want. 30K backlinks is easy in 6 months. 30K quality backlinks in six months is not so easy.
You can get 5 million backlinks in 6 months using the DP co-op network if you know how it works... It is not a viable long term strategy however as Google have started to notice people exploiting it (some of the sites that are #1 for terms like "loans" are using it), and sites using it will more than likely get slapped. If you go after it, be warned.