For suite101 website, the big problem i see is the left side of article pages. It has a lot of ad units and is confused with site navigation. Probably many users click back or go to google search again after click an ad.
IMHO, displaying categories in left side and fewer ads in a right side should solve their problem (if can be so simple).
Anyway, Matt Cutts says in Wired interview he understand why suite101 is penalised, is pretty sure about this site.
Maybe you can add another wrong things on this site, to make a list with possible factors.
I am still working to restore my traffic.