Web semantic is heavily related to Trustrank now...the more trust juice you can direct to your site - the better response you can get. Of course the whole campaign of link building must "seem natural" if you want to be a consistent performer for the adwords competitive keyword phrases - surely Google treats them differently than the non competitve keyword phrases.
Although No-Follow tags are not so important in terms of pagerank evaluation or anchor text votes, some of them are surely one of the heaviest links you can ever get. Try getting your site in a wikipedia page - you will see what im trying to say here. And Google might not take the no-follow into account (thats what they say) - but im 103% sure they monitor them all around. No-follow tags IMHO are one of the biggest proofs that the link campaign was indeed "natural".
First thing I do with a new domain, with often stratospheric effect is :
Search for the related forums of the related keyword phrases
Pick out all the high pagerank pages one by one (Parse them)
Add my link there in a 4:1 ratio ( 4 being my targetted keyword phrases, one being a related LSI phrase)
Add my links to the other pages as well.
Find the right place to Outsource ( 100 forum postings cost me $5 )
----This is not even a tiny portion of the link building I will do for the next few months, but keeping in mind the domain is fairly new - it gives my site a very good chance to sip in some relative authority before going the speedy way.
Search Ranking can give me very targeted traffic - THATS IT! I would never rely on it 100% (Any More!) and rather try all the other traffic methods for my sites. The MFA days are long gone, and now only long term internet business models can survive.
This can go along forever, but what I have learnt from experience - a business is a business - no matter if its offline or online - you can treat whatever traffic you get like a king OR you can kill the goose to rip all the Golden Egg at once - and get NOTHING!!