The basis for such assignments is your assessment of whether or not said businesses are following your idea of an acceptable celebration of Christmas. If there are nativity scenes, references to 8-lb. baby Jesus, or the clerks greet you with "Merry Christmas" (just like the shepherds did in the bible), then they qualify as "nice". But if they say "Happy Holidays", they are clearly tools of the devil and must forever be branded as "naughty".
(Side note: what about the Little Drummer Boy? If a place has him in their decorations, is he naughty, because he's not in the bible? Or is he nice, because he played drums for baby Jesus?)
And once you know if a place is naughty, then...well, I'm not sure what you are supposed to do with that information. I guess you show them the love of Jesus by boycotting them or something. That way, you ensure that good God-fearing Christians like you will be a light on a hill, just like Jesus said. Only you won't, strictly speaking, carry that light into an actual dark place or anything. Because Jesus wouldn't want that.
I hate to state the obvious, but this is a horrible idea for a website. The fact that it's driven by a large evangelical church is mind-boggling. Is the church of Jesus Christ in the business of complaining, or of actually ministering to people? One would think it's the latter. So how is this ministering to anyone?
I don't profess to know all that the world needs, but one thing it doesn't need is more Christians complaining about how unbelievers don't embrace our values. They're unbelievers; what do you expect them to do? We should all be amazed that they allowed "Merry Christmas" for so many decades!
We are to be a light to those who don't yet believe. Unbelievers need Jesus. They don't need angry Christians being more divisive toward them, perpetuating the stereotype of the hateful Christian. They need Jesus. They need to know your story. They need to know how Jesus changed your life, healed your wounds, restored your marriage, brought back your prodigals, and gave you hope in this life and for eternity.
The Jesus they need to hear about never once complained about how culture was shutting Him out. How in the world can any follower of Jesus think it's OK to do the very thing Jesus never did?
I am truly saddened, as a believer, by this site and the perceived need to paint a scarlet "N" on those businesses which don't have the "right" kind of decorations. This hurts my heart.