HTML tags for SEO emphasis
Some keywords should be put in bold typeface to point search engines in the right direction.
When you're writing web pages you will probably want to stress a certain word or two. Compared to header tags, using the <b> option in your HTML code to make a word stand out doesn't carry as much weight with search engines. Don't dismiss it entirely, though, because it does count.
Anytime you stress a word to make it stand out to your readers, you're also stressing that word to search engines.
Using Bold Text should be done whenever it fits into the flow of your content and matches the look and feel of your web site.
Many WYSIWYG (What You See Is What You Get) HTML editors do this for you on the fly, but make sure you check the code to make sure it's clean and not cluttered with extraneous tags.