AFC Bournemouth chairman Jeff Mostyn was interviewed by Bloomberg about the upcoming Barclay's Premier League season, and during the course of the interview Mostyn indicated that the Cherries would be entering a partnership with an MLS side sometime in the near future. The brief article that accompanies the video states "The club is also courting a formal relationship with Major League Soccer team Philadelphia Union." This should come as little surprise to anyone, however. Mostyn is friends with Union CEO Nick Sakiewicz, and there had been rumors that there would be this sort of partnership announced.
Quite frankly, I'm not exactly sure what benefits either team will reap from this arrangement. It's unlikely any players will be loaned from one side to another - Bournemouth will need all hands on deck to even stay up in the Premiership this season, and it's unlikely the Union have anyone who could play at that high a level to loan to the Cherries. Bournemouth is unlikely to gain many new fans by this partnership, as most Union fans who would be interested in rooting for a team in England already have one they root for and are unlikely to stop rooting for a Chelsea or Manchester United for Bournemouth. Philadelphia may gain a few more fans in England, however that too seems very unlikely. The only thing I can think of is giving the Union players a place to train during the offseason and the ability to say they're affiliated with a team in the Premier League (at least through May 2016).
It's worth noting that the Union had a strategic partnership with Club Deportivo Saprissa starting in 2012, however the only tangible result of the arrangement was the Union signing Josue Martinez, who spent one season with the Union and one with the New York Red Bulls before heading back to Saprissa.