It is called end of trial. Or the adds mainly. All the stuff should work now, there is just a limit to how many thingies you can have in the free and while I had removed several auto-generated pages, it apparently did not remove the widgets created for them.
The colors are different due to a theme change. The mobile site has the same theme colors as the main site, so I am trying to find one that would work better for mobiles as per your request.
Yes, paying removes the ads completely for everyone. Pay by credit card gives me a price of 6,88e for 30 days, or 66,03e for a year. Paypal rates are in USD: $8,95/month and $85,92/year. The longer plans are cheaper.
Personally I don't even see the ads, using Firefox with Adblock Plus installed.