Even in spite of the fact that, you wish to have good directories, they can turn bad over a period of time through link farm.  Although it is true that for the common understanding of the people, links provide a source to click and know more but in the world of web, this may not be link farm may not be advisable with the fact that the negative impact would cause a harm to the web site and web site owners may not be willing to continue to work on web site.

Therefore,  as long as you have a wordpress and Pligg which are open source to build and link farm, you will also receive blogger support for indexing link farm.

Link building farm is always in social media and business media as long as it does not result any sort of spam and does not leave a negative impact on the users. There are a quite few exchanges of those who already link farms who are of the opinion that the benefit of blog is wide and produces good results to an extent. There are many viewers who are of the opinion, building a link farm is good which can earn  good revenue and when the successful opinions are exchanged, the success rate of link building farms will increase. Therefore, there are some benefits with link building farms and there are some losses with link building farms, but it can be balanced.