The highest yield I've ever seen on a dividend stock was about 10%. I know that's not a very high yield, but it's still pretty good. Dividend stocks are usually safe investments: they're often stable and reliable, so they tend to pay higher dividends than other stocks.
But if you've got some extra money lying around and don't know what to do with it, investing in a dividend stock might be a good idea—you'll get a little bit of extra cash every year. I've seen this kind of thing happen when I was looking at my investment options.
In fact, there was one company that offered such an amazing dividend that I had to check twice before investing because I thought there must have been some mistake. But no—it really did pay that much.