For folks who listen to Fighting for the Faith Chris Rosebrough has a podcast up discussing this apparent happening over here.
There's no indication that despite iPad Mini give-away offers that Driscoll's Ephesians study Who Do You Think You Are managed to get on the NYT bestsellers list. That even the theme of Christian identity and discipleship were themes explored by former MH leaders Wendy Alsup and Bill Clem a few years before Driscoll published his own book might be even easier to miss. Well, if gift give-aways don't spike sales then perhaps crashing a conference affiliated with one of your most prominent, vocal and public critics can get you some airtime.
Driscoll considered MacArthur to be an important formative influence on his early Christian life so for those who don't know that not-insignificant detail it does make some sense that Driscoll might still hope to win the approval or at least a lessened censure from MacArthur, who has obviously become one of Mark Driscoll's most publicly recognizable critics over the last seven years.
Maybe Mark Driscoll deigned to talk with MacArthur about Song of Songs? Wouldn't bet on it myself.