WebGuerrilla - 9:36 pm on Feb 12, 2002 (gmt 0)

At best, they are treated as just another occurence on the page. If you use a 1000 character tag, then it will have a negative impact on the overall density (for your optimized term) of the page.

Keep them short and sweet. Use them to simply reinforce your key phrases in your title, descriptions, and headings.

Some people here use the no comma method, while others preffer commas. You can do use the site search to find many threads where we have debated the topic. :)