Exchange-traded funds offer a convenient way to invest in sectors or niches that interest you. If you're interested in investing in stocks that pay out sizable dividends, the Global X SuperDividend ETF (NYSE: SDIV) could save you a lot of trouble. Instead of trying to figure out which companies will perform best, you can use this ETF to invest in lots of them simultaneously. Its yield recently topped 8%.

The basics
ETFs often sport lower expense ratios than their mutual fund cousins. The Global X ETF's expense ratio -- its annual fee -- is 0.79%, which is higher than many ETFs', but lower than that of the typical stock mutual fund. It's relatively small, too, so if you're thinking of buying, beware of occasionally large spreads between its bid and ask prices. Consider using a limit order if you want to buy in.

This ETF doesn't have much of a performance record yet, as it's very young. As with most investments, of course, we can't expect outstanding performances in every quarter or year. Investors with conviction need to wait for their holdings to deliver.

The fund is rather small, too, so if you're thinking of buying, beware of occasionally large spreads between its bid and ask prices. Consider using a limit order if you want to buy in.

What's in it?
Several big dividend payers have performed extremely well over the past year. PDL BioPharma (Nasdaq: PDLI) surged 45%, collecting royalties from a slew of medications. Its stock recently yielded 9.3% and the company will remain attractive as long as it's able to add new drugs, since existing ones will eventually have their patents expire. Tobacco concern Vector Group (NYSE: VGR) gained 19% and recently yielded 9.1%. It's a profitable company, but it also offers reasons to worry, such as a high payout ratio that suggests its dividend isn't sustainable and a shrinking base of smokers in the U.S., partly due to increased regulations and taxes.

Offshore drilling contractor Seadrill (Nasdaq: SDRL) advanced 17% over the past year, and recently yielded 8.2%. It's poised to benefit from increased interest in deepwater drilling, and has been profiting from the high price of oil.

Other dividend payers didn't do as well last year but could improve in the years to come. Health Care REIT Omega Healthcare Investors (NYSE: OHI) only gained 2% over the past year, partly over worries about cuts to Medicare that could threaten Omega profits. It recently yielded 7.8%.

The big picture
A well-chosen ETF can grant you instant diversification across any industry or group of companies -- and make investing in and profiting from it that much easier.

Learn about the 5 ETFs That Could Soar in 2012. And if you're looking for some great investments beyond ETFs, consider these 12 Dividend Stocks for 2012.