How many people in America are browsing the web on their cellphones? 90 million. And 62 million of them routinely view blogs and social sites through their phone's web browser. These numbers are up by several million just since the end of last year, says comScore's latest report.

If you're not one of those people, you probably know a few of them. Mobile web use is growing fast, and your website, if it works well for mobile browsers, is now able to communicate effectively with a ton of potential donors, partners, and service recipients at any time or place they want.

But if you're like most organizations, you've not yet developed a strategy for addressing this audience. If that's true, don't feel too bad about it, because most retailers are in the same boat, says a study released this month.

That study reports, importantly, that 89% of retailers firmly believe that mobile web use will be as popular as e-commerce, so they can see that mobile web use is worth responding to. Despite this, less than a fifth of retailers have actually implemented a mobile strategy -- less than one in five! And almost a third of them haven't even made a plan for it at all.

This means that there's a growing number of mobile web users who're looking for good and easily accessible content, but who're regularly finding sites that either a) take too long to load, b) don't fit on the screen, or c) are just broken or illegible. Take a look at this quick summary of a survey that indicates that, when encountering these problems, over 60% of users won't come back to that site again, and 40% of users will look for a competitor's site that performs better on their device.

This boils down to two important conclusions: if you're not developing a mobile strategy now, you should be; and if you are, you're positioned to catch the attention of a whole lot of people -- any time, any place, with the message you choose to give them.

So the next time that lady in the coffee shop flips out her iPhone and starts tapping, ask yourself: Couldn't she be looking at my site? Because, ready or not, she just might be.

Photo credit: “iPower,” by Randy Rogers.