There are many concerns that you should have when you use tables in your web site design. One concern that is overlooked quite often by well-meaning designers who are trying very hard to use 'white-hat' methods is accidental spamming.
Accidental spamming occurs because tables allow you set a background for each cell. Many designers use this feature to set the cell's background color rather than setting the entire page's background color.
Lets use the example of a page with a typical white background color and a table. The designer sets the background color of one of the cells to red and then used white text for users to read.
While the site's visitors may have no problem reading the text in the cell, the text inside the cell is the same color as the main page background. A search engine's spider may consider it spamming because the designer is trying to use the same color text and page background.
You have to remember that the spider is just a machine and may be coded to think that the designer is trying to hide the text! This may cause your site to be penalized pretty severely.
