Bold text to increase ranking

Hi all

A quick question that I haven't been able to find an answer to.

Emboldening text - does it increase rankings?

And is using <b> the same as using <strong> or external CSS (font-weight:bold)?

Do they rank equally as well?

In my experience using an embed <b> bold tag does have a slight (and I stress slight) benefit on SERPs.

I don't believe this works using external CSS as most bots don't read them. I have seen people using <h2> tags with hyperlinks inside them but this isn't correct W3C code so in my mind you shouldn't realy do it.

What I have done in an SEO comp was make all of the keywords within the body - that weren't links - bold. This seemed to have a slight improvement but there were other variables affecting things at the same time. Don't go over board - if it looks right and reads right then it is right!