AT&T loves to trumpet the importance of the so-called "quick messaging" segment to its bottom line -- the QWERTY-equipped featurephones that keep the teens and tweens texting 24 / 7 -- so it's no surprise that of the latest batch of devices they've added into the mix from Samsung and Pantech (which we missed while caught up in the week's MIX10 activities), three of the four have full keyboards. The Strive from Samsung gets real in stores on March 21 with a 2 megapixel cam and vertical slide for just $20 on contract with rebate; the Sunburst comes on the same date for $40 with the same cam but a rather attractive full-touch design. On the Pantech side, you can choose from the portrait QWERTY Link (pictured left) or the Pursuit portrait slider, though neither has been blessed with a price or release date just yet. Perhaps more interesting than the phones themselves is the fact that the devices are the first to get hooked up with a host of new services from AT&T, including a cloud-synced address book, a media sharing service called Mobile Share that allows you to transfer videos and pictures between devices for a monthly or per-transfer fee, and so-called "Next Generation Messaging" that adds group texting capability, a threaded view, and a unified inbox -- smartphone-caliber features across the lower end of AT&T's range.