I purchased American Capital (ACAS) in 2008 when this business development company was trading at $30 and was yielding 13%. Just a few months later the company suspended its dividend payment, and I sold it immediately. The thing to learn from this example is that investors have to check the sustainability of distributions in light of cash flows generated by the business, the amounts of debt relative to total assets and the amounts of interest expenses. If you find a high yielding stock, which generates enough cash flow growth and has limited amounts of debt, then it could be a buy on the next dip.

While companies are not contractually obligated to share profits with shareholders, it is nice to see when boards increase dividends and declare stock buybacks, This typically sends positive signals about management's confidence in projected cashflows, generated by the business.
In my portfolios I like to hold stocks with different yield/dividend growth characteristics. I do tend to focus mostly on the sweet spot of dividend investing, where yields are somewhere between 3% and 5% and dividend growth is in the upper single digits or in the double digits.
I do realize however that some investors are interested mostly in current income generation, and not so much about future dividend growth. Thus recommending Wal-Mart with its 2% dividend yield to an investor who wants to generate as much income as possible now might sound ridiculous. Just because one wants to generate as much income as possible however, doesn't mean that they should throw caution away with the wind.