how many keywords

I am pretty confused about keywords.How many keywords should i use?First I used more than 500 keywords:S , that was a fault and now there are just 3 keywords .Shall I increase the number of them ?If I use 20 or 30 keywords, do Search Engines penalise me?
When I change or add some keywords , may I lose rank in SEngines?

 

make atleast 10 major keywords and 10 minor keywords... and search in the key search tool what is the most effective keyword use by the visitor to the related site... as far as i know more keywords to use is considered as spam...

 

submit express analyzer suggests 20.

 

I think 15 to 30 keywords is good.

 

everyone are talking about keyword or keyword pharses?

How many words should we use in key pharses?

 

Keywords should be 10 to 20 (just keep it to a minimum coz in the long run, your keywords will expand naturally)

Keyword phrases- just make it short, descriptive and direct to the point (5 words is long enough)

 

I agree with aira... My keywords doesn't exceed the limit of 10-20 and maybe you should keep tracks of your Major Keywords rather than your Minor...

 

Use synonyms. Use the google tools in Adwords and get other related keywords. Put in the url of your competition or if you are an affiliate, of your parent site.

Gregg