Following the conclusion of their four-game set against the Braves, the Mets made a minor deal. It was about as minor as trades come, really, but it was technically a trade. Short version: The Mets dealt two low-level minor leaguers—OF Julio Concepcion and RHP Andres Perez—to the Angels. In return, the Mets received "an International Signing bonus allotment."
If you're confused about what "an International Signing bonus allotment" means, you're not alone. According to Adam Rubin, MLB teams now have spending limits when it comes to signing international 16-year-olds—the closest thing MLB has to a spending cap, in essence. However, teams can trade for each other's cap money, which is what the Mets just did.
Concepcion has appeared in just 6 games for Brooklyn this season, while Perez was still at rookie-league Kingsport. In other words, neither player is anywhere near making the majors, if they ever make it there at all. So this (very) minor move could signal more international spending by the Mets in the near future, or (more likely) it could just signal Sandy Alderson & co. using spare parts to take advantage of the new rules and buy themselves some insurance against future contingencies.
Hopefully, this has taught you a little bit about the new landscape of international signings in MLB. What it taught me is that there's no way to google the phrase "international 16-year-olds" without feeling like a creep.
Update: Baseball America has the details on the slot value in the trade:
The Mets will receive the Angels’ No. 2 slot value (the No. 51 overall slot), which carries a value of $360,500. The Mets now have an international bonus pool of $3,025,100, while the Angels’ pool drops to $1,633,200.