The reason this technique tends to have merit is because at some point, dividend yields on stocks become so attractive that they basically become bonds with huge upside potential. As Benjamin Graham pointed out more than half a century ago, this is especially true in the case of companies that have no debt and pure-equity capitalization structures because the common stock of a company with no prior claims can ipso facto be no less safe than bonds in the same firm would be if issued. (This fact is often not understood by those who confuse volatility with risk. They are not the same thing.)
In other words, when sustainable dividend yields - that is, dividend yields that you can be fairly certain aren't in danger because the company that pays out those earnings generates profits far in excess of the cash sent to shareholders - reach a certain point, investors, whether consciously or not, become much more willing to wait for a stock to start moving upwards. Who cares if your shares only increase from $19 to $20 in a year if you are collecting 7% or 8% in a tax-free account surrounded with a world of 1% bank rates? In effect, you are being paid to wait for things to recover.
Better yet, if the earnings are plowed back into more shares through a dividend reinvestment program (or DRIP as they are sometimes called), the investor is much more likely to generate profits in their portfolio far earlier than they would have if they'd merely bought and held. (For more information on this phenomenon, see Jeremy Siegel's book The Future for Investors: Why the Tried and True Beat the Bold and New.

