That means it's also time to get e-commerce sites ready for the Christmas rush - change your colour scheme if it's seasonal (even if you just switch to a snow-capped logo on your festive pages), think about special offers and discounts, and keyword your product descriptions for Christmas.
It's not just because I'm a copywriter that I think that last point is rather important - in the run-up to Christmas, there are unique SEO opportunities that you just don't get at other times of year, and you're gonna need the right keywords on your e-commerce site if you're going to capitalise on those.
Consider the below graph of Google Trends data for 2010:
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