MySpace, although still much larger than rival Facebook, seems to have conceded that Facebook's new platform strategy is a good one. MySpace already lets developers create Flash widgets for the site, but co-founder Chris DeWolfe is quoted in the FT saying "The [Facebook] platform is interesting...We’ll probably offer users the choice of both.” In other words: perhaps a MySpace API in addition to the widget embedding.
DeWolfe's quotes are too vague to draw any concrete conclusions, but certainly they need to react to the buzz and frenzied developer activity around Facebook. Contrary to their established tactics of simply banning widgets they don't like, they'll need to come up with a comprehensive system that lets developers know exactly what they can do, while preventing malicious uses (yet another MySpace security issue is floating around this week, which highlights the risk of letting users embed code in profiles).
If given the choice, would you develop for Facebook, or MySpace, which is at least twice as large? Perhaps it'll be effortless to develop for both?