Google presented instant/realtime search results few days ago. While there was some buzz around the web, it was not publitized as an Apple keynote until the previous day. Google likes to do a sudden strike, a big impact not by media coverage but by the product itself (as always, there are exceptions, like Wave).
Now Microsoft semi-defends saying that they already had prototypes of real-time bing search one year ago. While it can be perfectly true, the difference between an experiment and the re-scaling needed to allow real-time results is huge, and the fact is that today Google has it and other search engines don't.
While I personally like the second approach (too many non-tech blogs about everything around the net), many posts are hidden "defenses" against claims, previous versions of IE and their problems, etc. They have to defend the new version because of the burden of previous IEs, they have to make much more noise about IE9 than google about Chrome.
In real life you will probably know at least someone who loves to tell everybody how good he is, what incredible things is doing (or more typically is going to do). Those are the noisy small rivers.
And then, you might know one guy that is more shy. That doesn't generates much noise. That might not be willing to create the ultimate application to conquer the world, but does small things here and there. He or she might be a deep quiet river.
The noisy river will probably either don't do anything, or create proof of concept-quality results. It might work, it might even look nice (depends on the resources or the environment), but internally the quality will be from normal to terrible.
To switch examples, Google Android's platform versions are an example of this: Advertised to the death as the perfect updateable solution (partially by using Java), in the end a piece of crap that ressembles J2ME but more recent. Locked down to operators, with breaking changes and incompatibilities, generating a huge fragmentation of their platform market segment, and even forcing users to root/unlock their phones to be able to keep up to date.
I'm 100% certain there are a lot of close real-life examples. Noisy rivers "expend more in marketing than in development", it's easy to see someone all the day cocky about something that then is not so incredible.
The quiet river works is the opposite. Tries things, develops real usable applications (maybe not full products, but with a decent to excellent quality) and many times just doesn't publitizes them. I know a few examples of this, and I get impressed sometimes when I see things they've made without telling almost anyone.
And the best thing is that usually the code inside is also pretty good. But maybe because they're shy, maybe because they don't like to or need to, the noise they make is small or non-existant.
The only problem with the quiet rivers is that sometimes a noisy river might flow near and get all the attention. While this can go from accidental paralell thinking to actual stealing of ideas, in general the one that loses is the one that makes less noise, and the other gets all the merits.
For me, I try to be a quiet river. I post some of my experiments, findings and thoughts here in this blog and apart from "echoing" to a few social networks try not to make too much noise, partially because I think is not worth it (I don't do anything extraordinary) and partially because I prefer the content to speak for me and attract those interested.
Try not to make too much noise, let your actions shine and delight others, and the attention will come. Look at the code and say "Do I feel proud or at least sattisfied with this? Would other like it if they were able to see the internals?". Many times those advertising constantly their skills and shiny new products actually have lower skills than you might initially think (or their product is rotten inside).