This week Samsung announced its new mobile “platform,” bada, which looks like a key piece in the company’s “smartphones for everyone” strategy, the goal of which is convert millions of lower-end phone users to smartphone owners. What exactly defines a smartphone is an open question, but if you’re Samsung, it seems to include an app store, as well as support for multitouch screens and a huge variety of sensors, including accelerometers, tilt, weather, proximity, and activity sensors. Also unclear is whether bada is an OS or something else; it’s built on the Linux kernel and will use Samsung’s proprietary user interface, already seen in its high-end “feature phones,” like the Jet.

(In Korean, bada means ocean, and the marketing campaign plays off of that in rather predictable ways.)

Confusing things even further, Samsung will continue to produce phones running Android, Symbian, Windows Mobile, and Linux Mobile. The introduction of bada points to the possibility of a lower tier of smartphones, with Samsung’s highest-end devices still running one (or more) of these third-party operating systems. Backing that up are Samsung’s statements that having a proprietary OS will make it cheaper to use, easier to market globally, and more customizable to the Samsung brand. (TechRadar has more on the platform and where it might fit into the mobile phone ecosystem.)

One thing that Samsung noticeably hasn’t done is demonstrate any bada phones–not even a prototype. Instead, this week the company showed off sample applications in the bada development environment, which it released to partners on Tuesday, along with a software development kit. Samsung looks to be trying to jump-start the bada app store well before any phones appear; a fuzzy “first half of 2010” was the announced timeline for the first bada phones. The company already has development partner agreements with Twitter, Blockbuster, CAPCOM, EA Mobile, and Gameloft, and it’s trying to make the platform attractive to independent developers with a bada Developer Challenge, a chance for them to win as much as $300,000 from a $2.7 million pool by creating new apps.