Update [2017.06.19] – I just received my third installment of up to 10 rides at 50% off within the past three weeks. HOWEVER, this time the promotion seems to be targeted for use anywhere “in the United States.” Previously the promotion was only available for use in specific cities within the U.S. The email subject line is the same as posted below, but the terms and conditions have changed. Check your email and let us know if you were targeted. The new offer expires on Sunday, June 25. 
NEW terms and conditions:
Promotion valid only for riders who received this email from Uber. Discount expires at 11:59pm on 06/25/2017. Offer has already been added to rider account. This discount is only valid on uberX, uberPOOL, uberWAV, uberASSIST, and uberESPAÑOL in the United States. Maximum discount of $10 per ride. Maximum of 10 rides per rider. Discount does not apply to surcharges, tolls, or Booking Fee. Terms subject to change.
Uber is targeting users in select cities with a 50% off promotion on up to 10 rides with a maximum discount of $10 per ride. No registration or promo code is required, and the offer is automatically being applied to targeted accounts. See the terms and conditions below to see which cities are eligible. The promotion is good through June 18.
The subject line of the email is “You’ve got 50% off rides.”
Terms and Conditions are as follows:
Promotion valid only for riders who received this email from Uber. Discount expires at 11:59pm on 06/18/2017. Offer has already been added to rider account. This discount is only valid on uberX, uberPOOL, uberWAV, uberASSIST, and uberESPAÑOL in New York City, Washington DC, Seattle, Los Angeles, Miami, Las Vegas, San Diego, Atlanta, Denver, Dallas, Orange County, Portland, and New Jersey. Maximum discount of $10 per ride. Maximum of 10 rides per rider. Discount does not apply to surcharges, tolls, or Booking Fee. Terms subject to change.
This is the second week in a row that I have received this offer. The first one was valid through June 11, and this extends the offer to 10 additional rides through June 18. Note that the 50% off will only apply on rides within one of the targeted cities. My account is registered in Seattle, and an Uber to SeaTac airport received the discount last week; however, my ride from the Minneapolis airport to my hotel did not receive the discount. This promotion is applied BEFORE any credits in your account, such as the $15/month Amex Platinum credit, as shown on my fare breakdown below.
Let us know if you were targeted in the comments so we can gauge how widespread this promotion is.
If you aren’t registered for Uber yet and plan to signup, consider using our referral link to get $10 off your first ride!