For example in forums, if thread named : SEO your website now so the H1 will be the title I thought of applying H2 as keywords , by giving the thread tags the H2 for example above <h1>SEO your website now</h1> <h2>SEO, SERPs, website, easy, tips, tricks</h2> is this considered stuffing?
abdobasha2004, maybe, because, there are a lot of sites that should be penalized a lot of time ago, but they are not. And one more thing, I doubt that there is a penalty for commas in h1-h6 titles, 'cause in your example it looks stuffing but in other titles may not. For example, <h1>The most popular SE</h1>, <h2>Google, Yahoo, MSN</h2>, <h2>ASK, AOL, Lycos</h2>