Fans of chunky payouts didn't mind seeing shares of Windstream (NASDAQ:WINMQ) tumble nearly 10% yesterday, as long as they weren't already investors.

The regional telecom services provider tumbled after posting mixed quarterly results , a move that pushed its already meaty yield up to a tantalizing 11.75%.

Naturally, the income investors already owning a piece of Windstream don't see it that way. It will take nearly a year's worth of dividends to cover the ground that the stock itself lost in a single trading day.

The report wasn't that bad. Pro forma revenue declined 1% to $1.55 billion from last year's third quarter, but it was actually a welcome $15 million advance sequentially. Windstream's adjusted profit of $0.12 a share fell short of the $0.13 a share that analysts were targeting, but that shouldn't come as a surprise. Windstream missed on the bottom line in each of the four previous quarters, too.

How sustainable is a company's dividend? That's the big question.

Some skeptics -- including fellow Fool Dan Radovsky -- don't trust the way that Windstream's accounting for adjusted free cash flow. They feel that it gives the illusion of a bigger cushion than the company truly has in keeping its hefty payouts going.

No matter where you stand on the matter, we can all probably agree that Windstream's ability to continue to keep these big disbursements going is related to its ability to sustain its business.

Providing telecom services to consumers in rural markets may seem like a smart idea. The big boys stay away, leaving opportunities for second-tier telecoms Frontier (OTC:FTR) and the larger CenturyLink (NYSE:LUMN). It's probably not a surprise to see all three companies sporting ridiculously thick yields.

The difference between Windstream and the other two companies, though, is that Windstream disappointed investors this week. Frontier managed to meet Wall Street's profit target of $0.07 a share on Tuesday. CentryLink -- now the country's third largest local phone company -- saw its stock climb on Thursday after offering up encouraging guidance.

Does this mean that it's a great time to buy into these high-yielding peddlers of local phone services?

The problem, as you can probably imagine, is that even rural customers are kissing their landlines goodbye. This leaves Windstream trying to offset the decline in traditional telco services through broadband and corporate services.

It's working, somewhat. Business revenue climbed 3% during the quarter, now accounting for 58% of Windstream's revenue. Consumer broadband services grew even faster!

There's always the risk that technology moves on, leaving Windstream behind without the capital necessary to invest in the future. AT&T (NYSE:T) turned heads this week with its plan to beef up its infrastructure to the point where it may not need hardwired customers in a couple of years. This is obviously a fluid situation that investors will need to watch.

For now, Windstream's CEO is making it a point to emphasize the security of the dividend. Given the company's ho-hum growth prospects, Windstream knows that many investors are just using it for its payouts. If it slashes its distributions, investors will probably follow suit.

Owning Windstream -- or Frontier, for that matter -- isn't the kind of investment that can be left alone. It requires a little more monitoring than traditional dividend-paying blue chips. Windstream needs to sustain its business to live up to the benefits of its fat yield. For now, it's mostly living up to its end of the bargain.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.