The BBC has just run a feature on what they call the Britishisation of American English (note the stiff upper lipness of their -isation rather than limp yankee -ization) and it would appear that some speakers in the USA are picking up terms from here and sprinkling them into their vernacular, without so much as a by your leave or missing you already. So words like snog and ginger have crept up the usage charts (and may even rival 1D's chart positions soon) and fixed expressions like go missing and chat up are also gaining popularity.
The usage graphs themselves are interesting things to have a look at because they show the increasingly scientific approach taken to language study that the digitisation of newspapers and books has given us. Plus, they reflect the influence of UK cultural exports like Harry Potter (and perhaps more precisely, in the case of ginger, Ron Weasley).
Of course, the media love to stoke friendly rivalries between the old colonial masters and their upstart offspring, with articles like this by Matthew Engle kicking off some hardcore peeving over the infectious disease of American English (which we covered on this blog here), but the picture has always been more varied than the caricatures suggest, and with linguistics now taking a much more nuanced turn towards language as performance and a marker of identity rather than simply reflecting fixed categories we fall into (British, American, male, female, working class, posh etc.) it's clear that more attention can be given to individual reasons why some British words might take off in the USA and others not.
All of this is a topic that we'll cover in ENGA3 as part of World Englishes and Language Discourses, because it's a debate about language use and its users that provokes so many different opinions. In the meantime, before we get to studying this in class, I'd recommend Lynne Murphy's excellent blog Separated by a Common Language and reading a bit of David Crystal's Encyclopedia of the English Language to see how American English developed its own distinct identity and continues to be the dominant English form spoken all over the world.
Edited on 28th September to add:
The Guardian have also run a comment piece on this topic today.