Dividend yields can also reflect important information about the company's status. For example, a company that has never lowered or stopped paying dividends is a "strong" company because it has the cash/earnings power to maintain its dividend regardless of the market. Ideally, a company should pay dividends for at least 10 years for an investor to consider the company as a "consistent payer."
Furthermore, when a company pays dividend, it generally means that it has more cash than it can profitably reinvest in the business, so companies that pay dividends tend to be older but more stable.
An important exception is REIT's and their ilk - to avoid taxation, these types of funds must distribute 90% of their earnings to their shareholders, so they pay very high dividends. Just look at stocks like NLY or CMO to get an idea. The issue here, however, is two fold:
- They don't have a long history of paying dividends. This is never a good sign.
- The REIT model is similar to S&L's in the past or banks in general - borrow money cheap and invest it at a higher rate of return. Once rates rise, borrowing becomes expensive, and earnings will drop, so dividend yields will drop, and that will make the stock price fall as well.
So a high dividend can be great [if it has been paid consistently] or risky [if the company is new or has a short payment history], and dividends can also tell us about what the company's status is.
Lastly, taxation on dividend income is higher than taxation on capital gains, but by reinvesting dividends you can avoid this tax and lower your potential capital gain amount, thus limiting taxes.
http://www.tweedy.com/resources/library_docs/papers/highdiv_research.pdf is an excellent paper on dividend yields and investing.