I have not seen a new PROPER portal enter REAL rankings for a year. There is too much clutter of spam and every possible URL variation from brands that do heavy SEO.
Well my busiest site, which is not spammy, has a low bounce rate, a NATURAL backlink profile and not grey or black hat, is ranking very well, for some very competitive terms. I started developing this site in Sept last year. Traffic is consistently over 3000 visitors a day BTW.
These spammy throwaway domains are very very annoying. But like I said above, they do get killed and slammed by google.
You should always build for long term and not short term gain. Some of the big sites that have been hit and that continue to get hit, I doubt very much have been developed using what is deemed pure white hat seo.
The webmasters that have been hit if they are honest with themselves no doubt will admit that they have used at least ‘gray’ techniques in the past.