SK Telecom (NYSE: SKM), the Korean telecom giant, made a bunch of investment-related announcements today, and among them, it will invest up to an additional $270 million to support their struggling wireless JV Helio, effectively pulling other JV partner Earthlink (NSDQ: ELNK) out of committing any further cash. We’ve covered that in detail on MocoNews here.

The more relevant part here it is also earmarked $110 million to invest in online businesses in U.S., though it didn’t give a lot of detail…the brief SEC filing from SKT today says this: “Investment in the Internet business in the U.S., which may include the social network service”. Cyworld USA, SKT’s social networking subsidiary here, hasn’t done as well as it expected, after being formally launched here last year, so this is probably the investment SKT will make to shore it up, or make acquisitions in the space.