Have you ever tried to squeeze a plumber into an online shopping cart? Unlikely. The fact is that most small to medium size businesses using the Web are not shopping carts. They sell services and products that just don’t work that way–like landscape design, consulting, and acupuncture.

So when SMBs are asked what they want most from a Web site, they’re more than likely to answer: more phone calls. This makes sense. In the non-shopping cart world, sales are made–or at least initiated–with a phone call. It’s worth wondering, then, if small businesses are getting maximum value from their Web marketing dollars.

This was once a simpler question to answer. Once upon a time, all you needed for online presence was a website. That was easy enough. Then it had to be better than competitors’ sites. So you built a better one. As websites became more sophisticated, the focus shifted to driving traffic, and then invariably to pushing only the right visitors your way.

And now, businesses are looking more carefully at how effective all of this is at converting their online spend to revenue. But what’s missing here? Have we forgotten that even before the Web, any sale started with the phone ringing?

Ironically, relatively few SMB sites have metrics telling them whether, and how many, site hits turn into phone calls–let alone intelligence like which keywords deliver the most calls. But if Web spend is intended to generate leads that are converted offline, how can you effectively measure Internet marketing ROI without this information?

Consider this. A good website should perform like a good salesperson–and it’s relatively easy to figure out if salespeople are bringing in more than they cost. And equally easy to see what kind of business is coming in. Shouldn’t it be the same for a website?

The abundance of metrics provided by Internet marketing solutions report how many visitors came to your site, how long they spent, what pages they came from, and what search terms they used. But if you convert visitors to customers offline, these pieces of intelligence don’t necessarily tell you if your website is a good salesperson, just breaking even, or underperforming.

Here’s where Web telephony changes the rules. Capabilities like click-to-call marry age-old phone calls with Web marketing. Instead of simply listing a phone number on a site, click-to-call turns any image on any page into a phone call trigger call to action.

Because the phone call trigger is now a click, it can be measured like any other. When sites visitors click the call icon, that action is captured. Now you can see how many visitors called–and exactly which page they called from–in the same way you can see how many pages they looked at.

So is Web telephony the Holy Grail for improving your Web economics? Debatable, like anything else. Yet converting more visitors to callers does reduce per unit cost of leads and in turn, overall customer acquisition cost. And knowing which keywords drive the best phone calls will add intelligence to your keyword bidding, optimizing your spend–something worth consideration in the face of accelerating keyword inflation.

The bottom line: There’s more to click-to-call than meets the eye. Yes, it generates more calls and builds a better experience for site visitors. But it’s the role click-to-call plays in building a better Web ROI that makes it so valuable. Properly deployed, it’s a game changer. Tell your CFO about it.