Hi, I recently observed that one of my sites recuperated its lost PageRank after I set almost all (about 98 %) of the outbound links "nofollow" and purged the thin content pages The has had a decent PageRank for a while, but then it dropped as the Panda/Penguin updates... I slightly refreshed it, but: no new content at all, no new links acquired at all, same design, just the "nofollow" and the erasing of thin content pages came as something new. It's a very old, simple site that I launched about a decade ago and used to be quite well established. The simple "nofollow"-ing of the outbound links and the purging of thin content pages made Google like my site. Indeed, it's more in-line with the trends and Google policies. A simple trick like this can make a major difference. Later on I tried this with other sites as well - results improved as well! Try it and it may help you...
Indeed, the nofollow attribute it's a but in nowadays for getting good rankings and having a great partnership with Google. Google took this action because the dofollow high pr links are influencing the search. So better not buy the links and do the clean seo.
But we still need clean, "do follow" links. So I personally don't think it's a problem to obtain clean inbound links from various sites. Just don't abuse the system.
article submission, blog commenting, forum posting is an easy way to generate back link, traffic and improve page rank.