Page rank sculpting refers to the act of using nofollow tags on internal site links to focus page strength or link strength to the pages and anchor text that a site owner wants in a search engine.
The reason we generally don't bother with pagerank sculpting any more is because "no follow" doesn't just stop the passing onwards of link equity, it burns the equivalent that it would pass on. So it really isn't worth using nofollow on internal pages as a result of this.
Very good answer I don't get why should anyone do Pagerank Sculpting? So far I know dofollow links help on increasing pagerank cause link juice follows from dofollow link only.
Page Rank sculpting is the act of optimizing your pages to flow Page Rank from your highest PR pages through to your most important internal pages while shunting PR from unimportant pages by directing Google to no longer crawl or index those unimportant or irrelevant pages.