Microsoft 's Kin 1 and Kin 2 phones aren't exactly dumbphones, but they're not exactly smartphones, either. They're being marketed as social networking phones for the teen set  (you can tell by the way the PR people showing them off are wearing weird thumb-shirts ), and they're actually a giant step forward for that category--but the line between the Kin and its more advanced older brother, Windows Phone 7, is sometimes blurry.
First, the specs (or at least what we know of them at the moment, thanks to Gizmodo ). The Kin 1 is smaller and less powerful than the Kin 2, and will likely be cheaper. It's an unusual square (or "squircle") vertical slider, with a small 2.6-inch 320x240 screen. It's also got a 5MP camera with standard-def video recording, and only 4GB of storage--that's important, since there's no microSD slot to add more. The Kin 2 is shaped more like a Sidekick or Motorola Cliq, with a 480x320 screen measured at 3.4 inches. It's got an 8MP camera and takes 720p HD video, and looking at the samples, the Kin's cameras can hold their own with any cameraphone out there. The Kin 2 also has 8GB of non-expandable storage.
Both the Kin 1 and 2 are equipped with Nvidia's Tegra processor, the same one used in Microsoft's Zune HD media player. The Tegra is a little underpowered compared to the Qualcomm Snapdragon that'll be used to power the upcoming Windows Phone 7 phones, but seems to do a decent (if not lightning-fast) job on the Kin line. Judging by initial impressions, the hardware is very high quality, especially the keyboards--after all, they're made by Sharp, the makers of the very sturdy Sidekick line. The one question mark is the Kin 1's performance with the Tegra chip, which seems less than stellar. But all in all, these are the specs of a mid-range modern smartphone.
It's the services that really set the Kin line apart. The phones are not proper smartphones, because the software can't be modified--basically, you can't install apps. But they're also not quite dumbphones, due to their connectivity, feature set, and cloud-based services which are in some ways better than that of most smartphones. Take Zune, for example. Microsoft's excellent Zune app takes care of the Kin's music and video, just like in Windows Phone 7. The internal storage might be paltry (4GB and 8GB are extremely low by today's standards) but if you have the $15 per month ZunePass, you can stream unlimited music over 3G or Wi-Fi, for no added cost. That's something the iPhone can't do nearly as well (iPhone apps like Rhapsody are not nearly as sleek and well-integrated as Zune).
The Kin line has three "headline features" that further set it apart: Loop, Spot, and Studio. The Loop is what you see on the home screen: It collects information from Twitter , Facebook , and MySpace, and updates that information in real time. Look at your screen and you'll see new tweets, text messages, whatever, and you can decide which friends to keep track of in the Loop. Plus, you can update your status to any or all of your social networks simultaneously. It's similar to Windows Phone 7's tiles or Android's SlideScreen app .
The Spot is Kin's method of sharing. It's a small circle (or, um, spot, I guess) at the bottom of the screen; you can drag pretty much anything into it (photos, videos, status updates, Web site bookmarks) to share via your preferred network, be it Facebook, email, or text message. You then drag a photo of the person with whom you want to share that info into the Spot to send it along. The Spot is unique to Kin.
The Studio is a major change, a huge push for the cloud. It's your own backup service where everything, from contacts to photos to text messages to call history, is kept. You visit the Studio from any browser, and it lets you do pretty much anything you do on your phone, like updating status or sending messages. Add a contact while in The Studio, and it automatically updates your phone--and vice versa. It's got a timeline, so you can see on a bigger screen the progression of your social life, and it supports geotagging, so you can see your photos on Bing Maps in the locations you took them.
As far as apps, you'll be stuck with the apps Microsoft includes, since you can't install your own. There'll be a browser based on Internet Explorer (similar to the pretty decent one on the Zune HD), an email app, and Bing search, but that seems to be it. No maps, no calendar, no games, no YouTube. Microsoft could add that stuff later, but don't bet on it.
Kin is a really interesting move from Microsoft. It's way more advanced (and flat-out more cool) than the Sidekick, probably its primary competition, though less capable than any modern smartphone. It's oddly complex, too, what with the streaming music and cloud-based backup and live updating status tiles, but teenagers steeped in technology will probably grasp those complexities fairly easily. It'll likely come in cheaper than typical smartphones (if Microsoft charges more than $150 for the Kin 2, they're nuts), but from the looks of it, you'll need a data plan. Are teenagers going to opt for a $150 phone with no apps over, say, a $50 Palm Pre, or a $100 HTC  Droid Eris? I have no idea. But they wouldn't go wrong.
The Kin 1 and Kin 2 are due out exclusively on Verizon this May for an undetermined price.