I was wondering if this would work or not. Create some divs or CSS elements of some kind then hide them in the CSS code by using some position hack like -1000px etc. same like you do to preload images, anyway, fill your tags with optimized content with keywords etc. so it will be read by the robots. I remember back in the early '90s many spammers would put pages of text in white on white at the bottom of pages using nonsense keywords to pick up traffic.

So I guess it boils down to:
Do search engines pick up content in CSS elements regardless of their state or visibility using a browser?

The Bots are probably going to see the SEO information you place in your flel and will penalize you if they decide that what you are doing is an SEO "trick" to enhance your positioning in their search lists. The Bots are getting smarter all the time.

Back in the old days people use to do it; even today some people still try to get away with it. However, as haslip mention you get caught your basically banned for life especially with google ad sense. I have seem many sites discussing about what people did to cheat the SEO system; which include using a small font, blend the text with background color, overload meta keywords with stuff that has nothing to do with the site. Search engines like google can sniff out the truth they somehow always find something if they believe the site to be suspicious.

Google specifically bans hidden info. That includes the example you mentioned above, as well as making the text the same color as the background. Just be aware that users with stylesheets turned off and who use text-only browsers will still see the text.

Its a sure way to to be banned by the search engines. Nowadats search engines have become very intelligent (this aint the 90s).
Instead of resorting to those black hat SEO's, try to put in lots of relevant content. write in a blog or maintain a forum.

So maybe it is no longer useful to use meta tag keywords. Style sheets are quite popular and there are places to put keywords when naming elements etc. so I was just wondering if search engines condsider the name of an element or look at the words in a class added to a div.

If every single page or publication of any kind on the net were the same size using roughly the same number of keywords then yeah content is where search engines should be ranking but I am thinking about how SEO and or CSS can be used to allow a smaller quality article or web page on a certain topic to rise above the larger and quite often spam oriented page or site. It really bugs me when I am looking for something and even though I use the advanced search methods with quotes and plus or minus I still see results on the first page of Google that are nothing more than stupid sites using some trickery to create a dynamic page based on your search terms that just link to other top level domains that look like other search engines or directories. Now this is the worst form of spam I can think of.

I never really thought about what that would do to help you in search engines. That's a pretty decent idea, but is basically cheating and I guess you'll get banned as they said. If you really want to have more keywords, make a forum that has a little bit of everything in it so then you really will have all those words on your website and put into use and search engines like Google won't ban you. Or have a website of articles ranging of subjects. Having a site with general content will probably get you more hits but you have to make sure that you really are putting effort into it instead of leaving forums empty just to have keywords.

What about a simple "content {display: hidden}" in the stylesheet? And then fetch the stylesheet, but ban the Googlebots from accessing the stylesheet with htaccess. Seems like something that might work

I have seen some directories use this CSS method to get the content indexed with Google & also the blank table method.