US Airways also has a bonus offer for online purchases made through their online shopping mall for up to 1000 miles. There is no need to register for this offer that you can access here.
Between now and December 31, 2012, you will earn 300 bonus miles when you spend $150 or 500 miles when you spend $250 or 1000 miles when you spend $500 or more. The maximum number if miles that you can earn under this offer is 1000 miles. These are in addition to the miles that you earn from the purchases.
You are essentially getting 2 extra points per dollar spend. The way I usually work these mall promotions, is to put a dollar figure to the mile earned so that I can compare them to straight cashback malls. Sometimes these airline related malls are better and sometimes they are not.
I wrote an article about getting cashback for your travel purchases and it does apply for most of other online purchases as well. You can use sites like CashBackHolic and Evreward to check the cashback percentages among multiple online malls.
Here are the terms and conditions of this offer:
Now through 12/31/12 11:59 PM EST receive 300, 500 or 1,000 bonus miles when you spend $150, $250 or $500 online through Dividend Miles StoreFront. The maximum number of bonus miles that can be awarded to each qualifying member through this promotion is 1,000 bonus miles. Returns, shipping and taxes are not eligible for bonus. Please allow 8-10 weeks for bonus miles to post to your account. Increased earning opportunities are for a limited time only and at the discretion of each individual merchant. Please check site daily for updates to increased earning opportunities.