RegDCP - 5:20 pm on Sep 17, 2012 (gmt 0)

If you have keywords in an h2 tag, for example, and it is similar in size to your body text, the fact that the words are in an h2 tag will give them more importance. The text in the h2 tag doesn't have to be a lot bigger than the surrounding body text to give it additional importance.

Not a lot bigger, but it HAS to be bigger.

IMO, Google judges relevance by what is presented to the readers.
EG. the visual presentation.

I have seen where h2 tags have been used to encompass the first keyword rich sentence in a paragraph while the visual copy did not show the emphasis.

If the words are not emphasized in the copy that the humans read, then why should the algo be told that they are more important?

Wouldn't that fall into a kind of cloaking where you are showing people one thing and showing the search engine another?