User blog comment:LostInRiverview/The Sims Wiki News - 13th December 2013/@comment-1997588-20131214071331/@comment-1519608-20131214174021

There's a reason for that. The choice of blue or green headers isn't random - it's based off the use of blue and green headers and borders in the news blogs - Sims News blogs have blue borders, Community/Wiki blogs are green. So, that's extended so that community features on the Main Page receive a green header and Sims-related features are blue. The amount of content on the main space related to community features outweighs the amount given to Sims features and news, so there is more green than blue on the mainpage.