My boss has a gigantic head and has spent $50,000 for an all-graphical home page. Will it help if we place keyword phrases in [alt tags] [comments tags] [a hidden layer] [text the same color as the background at the bottom of the page]?
I'm afraid that using keyword phrases in any of those places won't help get your home page found in the search engines. Alt attributes (alt tags) are ignored on images that are not clickable, so those won't help. Comment tags have nothing to do with search engine optimization, and are not indexed by the spiders, so don't bother with those either.
Hidden layers may actually help, but would most likely be considered spam by the search engines unless the content in them is exactly the same as on the graphical images on the site. If you simply hide keyword phrases in a hidden layer, be sure to look over your shoulder constantly, because your paranoia about one day getting penalized isn't all that paranoid; it could very well happen! If you like to sleep at night, this may not be the best route for you to take.
Your alternatives are to simply use the power of your Title tag and the power of the links pointing to your home page. You could also concentrate more on the inner pages (assuming they are not all graphical) and optimize them for the keyword phrases that are important to you.
Don't forget that you can always just use PPC ads and not worry about the organic/natural results. That is a very real option these days, and for those not willing to compromise a wee bit to gain natural rankings, it's probably the best one.
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