I guess I'm the odd one out here.
Although a lot of the questions here are a bit basic, the functional fit of the site is very close to what I think of as a webmaster's job, and can't think of another term that describes it well enough.
I also don't think that a SEO/SEM-focussed site would have any more traction than this site. Although a majority of the questions are tagged SEO, that's just a fact of our existence; SEO has to be considered in all aspects of running a site, as it's what we live or die by. I think we'd probably see a similar mix of tags (other than seo, since that would be meta) on an SEO-centric site.
I don't know what the answer is, other than better marketing and awareness building. Our community is pretty spread out and poorly defined (as this discussion makes clear) so there is definitely a challenge here, mixed with the fact that many domain experts run their own information resources and will likely be hesitant to cannibalize.
Overall, I'm in favour of maintaining the current name.