Not every entry on our list is new this year, but they have all done something innovative within 2011. Keep in mind also, these are consumer cloud apps - things that an individual would use for her personal work or livelihood. We'll have a separate list later on for enterprise cloud innovations of the year. The functionality needs to be delivered from the cloud app, as opposed to installing an application on a PC or smartphone that just happens to borrow cloud storage.

Hosting services are not cloud apps for purposes of this list; and there are plenty of innovative hosts to consider (we gave serious thought to Wistia), but in the end we decided that a hosting service is not really an application unless it provides a discrete function that goes over and above simple storage or sharing. Analytics, which Wistia provides, is right on the edge, but it's really a measurement of a byproduct of using the service as opposed to a function that users actually perform. That's not saying Wistia isn't a great idea; it just belongs on another list.

10. CloudApp. The largest single category of cloud apps for consumers is storage and retrieval, which is understandable because it's a service that everyone needs to one degree or another. What's interesting is how certain services innovate on this theme, and especially whether they give themselves room to continue innovating.

CloudApp is for Mac OS and iOS users at the moment, and its innovation is that it's building a little ecosystem around itself. It utilizes your choice of quick-and-easy gestures for designating a file or object to send to CloudApp's storage, the most basic of which is dragging and dropping the object to CloudApp's icon in the taskbar. In exchange for this gesture, CloudApp produces a URI which is copied to the Clipboard. From there, you can paste it into an e-mail, a tweet, or an IM message; when your recipient receives the link, she has instant access to the object.

The way CloudApp innovates is by incrementally enhancing what can be easily uploaded, and how those objects can be utilized in their native context. One example is screenshots: You can designate a key for taking a screenshot and uploading it in one fell swoop; the recipient sees your link, clicks on it, and sees your screen. There's no exporting or importing necessary here.

But what hoisted CloudApp onto our Top 10 list this year is how well the company is promoting Raindrops. This is an extremely clever, self-promotional idea for enabling developers to build their own tools that utilize CloudApp in similarly contextual ways, with the help of CloudApp's own API. One example the company created at the time this feature was launched in April 2010 is for Adobe Photoshop; since then, the community has contributed a truckload more, including an intelligent link interpreter for Twitter and a stand-alone CloudApp client for iOS called Stratus.

Here's an example (above) of another add-on you can't even see (which is a good thing): The maker of SparrowMail used CloudApp's API to develop a way to do simple drag-and-drop of attachments into e-mail messages, bypassing Mac OS' sometimes convoluted series of steps.

Building a community around something as simple as an app is a difficult thing for a small company to achieve, especially when it's in competition with a plethora of other vendors in the same category. CloudApp is pulling this off brilliantly. (It's worth noting that the service is built on the open-source Heroku platform from Salesforce, thus answering RWW's question from last year on whether developers will trust Heroku: Yes.)

9. Waze. What would be nice is if someone hired a few thousand cars to drive around each town looking for traffic incidents, and report on them in real-time. Let's see, $25 bucks per hour salary times 1,000 reporters times 50 cities... I'll get back to you on that idea.

Or, what would be brilliant is if someone leveraged the platform that's already in existence to enable a few thousand folks to do this job passively and voluntarily. Waze is a system that utilizes the GPS information being pinged back from iPhone, Android, Windows Mobile, and Symbian devices. It's been in existence since 2006, but last October the 3.0 version of the service introduced a fabulous new feature (so far, just for the iPhone users) that integrates with Twitter. This way, people can tweet on what's happening in their neighborhoods (including the good things, like street fairs) from right where they're standing.

Okay, maybe there aren't a thousand Waze users in a city like mine (Indianapolis) just yet, but it's surprising what you can find. There's updates on traffic accidents and reported police sightings (which are rarer in some cities than others). What Waze demonstrates is that there are ways of making use of data that can be collected passively from a crowd of users, in ways that do not jeopardize privacy.

8. Box.net. This is one of the services that comes to most folks mind when they know what a cloud app is. What's kept Box.net in the news, including just this month - and what keeps Box.net on our list this year - is a constant stream of innovations. Customizable synchronization is one example from last fall; and earlier this month, a completely revamped iOS app that enables features like uploading photos and videos to discrete folders. This puts Box.net on a par with dedicated photo-sharing services that simply can't expand its features list to Box.net's size. And just this morning, the company launched an enterprise-grade option for unlimited storage.

Next: Playing your own tune...