Om Malik has a truly insightful post over at GigaOM today about Yahoo’s controversial decision to sue Facebook for infringing on several patents. Malik figures the lawsuit stems from Yahoo’s ill-conceived plan several years ago to give Facebook access to the address books of hundreds of millions of Yahoo users. This was all about fixed-line Internet traffic at the time, of course, but as mobile Web traffic has ramped up the battle for the address book has expanded to wireless. (That battle reared its head about a year ago when Google removed Facebook contacts from its Nexus 1.) The carriers — who have long owned subscribers’ contact lists — are fighting to be the primary access point for that information, and they’re competing against both social networks and operating system providers. And I fully expect that battle to heat up in the coming months.