I'm a gold and have not flown with United on a revenue ticket since August 2012. (Having been 1K the previous several years).
Just got this:
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Map your next journey with more MileagePlus Premier qualifying miles.
For a limited time, you can earn 50% more MileagePlus® Premier® qualifying miles on roundtrip United-operated flights around the world. Purchase your ticket in United Global FirstSM, United First®, United BusinessFirst®, United Business® or United Economy® (F, A, J, C, D, Z, P, Y, B, M, E, U, H, Q and V fare classes).
Simply register, book and complete your travel by May 23, 2013.