By Jaspreet SinghJuly 30 (Reuters) - Reddit said on Thursday that choppy search-engine traffic affected U.S. user growth in the second quarter, overshadowing an upbeat revenue forecast ‌and sending its shares down about 12% in extended trading. Reddit's user growth is shifting ⁠toward international markets that generate less revenue than the U.S. Daily active unique visitors in the U.S. rose 6% in ​the ​second quarter, down from 7% in the prior ​quarter, while international DAUq jumped 28%. Reddit also forecast slower revenue growth in the third quarter. "The company's advertiser growth ​in the second quarter was 70% year-over-year.