United's shopping portal was offering a holiday shopping bonus this year -- in addition to the bonus miles you get from each merchant, they were offering additional tiered bonuses for your cumulative shopping through their portal during the holidays.
My bonus came through today and I netted 18,014 points for spending $1612. 13.6 points per dollar. Not too shabby :) The tiers were: 500 bonus miles for spending $150, 1500 for $350, 3000 for for $650, and 6000 for $1250 or more.
Here's the breakdown:
Like most of these mileage-related things, the trick is not being tricked into spending money you wouldn't otherwise have spent. In my case Yoox had a coat I'd been lusting for since last winter and it was half off the original price. And my current winter coat is like 5 years old and shabby. I always bring the wine to my in-laws place so I would have bought the Wine.com purchase without the promo. My one real addiction is expensive shoes, so the Nieman's purchase was for some cute Lanvin waterproof winter shoes and I needed something in that category now that it's winter.
Another big thing I learned in this process is that certain merchants do bonus days throughout the promotion, so it might be worth waiting a couple of days if a high-markup retailer (like Nieman Marcus) is only offering 3 points per dollar. I waited and bought my shoes on a promo day and got 12 miles per dollar. Low markup retailers (Best Buy, Ebay) never offer those kinds of numbers. Sometimes the bonus days will be listed in advance (see this example on The Points Guy) so you can plan when to buy what.
Make sure you look at the promo fine print so you don't buy something that doesn't qualify (for example, 90% of Sears.com doesn't qualify for any miles at all). Also, if you have miles with more than one airline/credit card, you can use a shopping portal finder to make sure you're getting the most points from the shop you're buying from.
Even after I'd hit the $1250 threshold, I found I had a few more holiday gifts I needed to buy (an expensive wallet, for example) and I had the good sense to log in to my husband's mileage account so that he could get some bonus miles too.
The bonuses appear 6-ish weeks after the promo ends, and the My Account link on the shopping portal lets you track your progress.