We’ve covered SwiftKey in its various incarnations a lot here on Android Community, and not without good reason. It’s gained notoriety as one of the most popular Android virtual keyboards, no small task when your app duplicates core functionality, even if it is adding in a lot more. Octopus Investments would seem to agree: They’ve invested 1.5 million GBP, about 2.4 million dollars, in the small developer TouchType.

SwiftKey X and its tablet counterpart have remained at the top keyboard replacements for a few determinable reasons. One, the app never stands still: hardly a month goes by without some sort of update, improving SwiftKey’s performance and predictive text. Two, they cover all the bases: a free preview version allows curious Android users to try out the keyboard before dropping a few dollars on the full version. And finally, they’re quite communicative with their customers and fans, allowing alpha and beta access to geeky types (hello!) who always want to try the latest version.

SwiftKey X regularly lands on the Editor’s Choice list in the Android Market, and its success made it one of the first apps offered in Google’s 10 Billion Apps promotion. It’s currently available for just $.10/£.10, though that may not last long – head over to the Android Market to get in on the reduced price. The company says it will use the cash infusion to strengthen its executive team and increase its presence in the US and Asia.