It looks like the database for the yields showing at the top of...

It looks like the database for the yields showing at the top of the list have not been up dated for quite some time.
I get the same sort of results sometimes through my trading platform's stock analysis tools, esp when the last dividend reported may of been pre- stock market crash profit results.

The tool is useful for quickly finding high yielding stocks. But I then will look at a company's announcements to see what the last dividend result was; and, to see if the board of directors have given any guidance on what the next six months dividend may be; then, do the calculations myself.

For example: Marbletrend Group Limited (MBD)

The list at the linked website is showing the share price as $0.063; a dividend of $0.02; yield 39.75% .
My trading platform is showing 31.8% .

The last dividend paid was $0.005. The directors have given a guidance for the next dividend (most likely to be paid in October 2010) payment of $0.005, bringing the full year total to $0.01 .
There is also the possibility of a special dividend payment of around $0.002.
The dividend is also fully franked at 30%, so depending on your personal income tax situation, you may wish to include that in the calculations.
This would bring the full year dividend to $0.0156 per share.

There is, however, a slight problem with the value of the current last sale share price of $0.063 for the purpose of the calculating the dividend yield.
If we look at the depth screen for the stock, we see that the nearest parcel on offer is at $0.068. But there is not a lot at that. So to get a decent size parcel we would have to pay at least $0.069 per share.

Our dividend yield calculation is thus:

100/(.069/.0156)
= 22.6%

Hope that helps :)
--Dan