Nope. Meta tags are pretty much insignificant in rankings today. Content is, while that's a very general concept comprised of a lot of different elements, generally the most important things in so far as that it gives you the flexibility to target various search terms; but a well-linked site is much easier to get ranked than one that is not. Incoming links are much more improtant than outgoing links, though how you link out and the balance between the two determine the sites "hub score" in relationship to its "authority score."
Originally posted by iTec Hosts
Content is a big factor in how a search engine such as Google ranks a site. Meta tags place just after Content and then links to and from your site.
What's important is not to overvalue SEO. The site still has to be comprehensible to human visitors, and beyond just being comprehensible it has to sell to visitors. Getting rankings and even getting traffic is secondary, in almost every case, to getting conversions.
The main things are to ensure you use proper grammar, spelling and puncuation to begin with. After all, would you buy a product, service or (guessing here) a house or business property from a site with tons of spelling and other mistakes? I know I would not.
Anyway, back to teh original question:
In general grammar itself isn't important to achieving rankings. Things like that quotation mark in your example are simply ignored by ranking algorithms. But, misspelled words and foreign language words do play a role, in that keyword density, placement, and proximity still play a role.
Originally posted by realestate
is html grammar important for search engine optimization, if it doesn't have any effect on looks and functionaliy of the site. For example if " is forgotten etc.
That is, if you have one paragraph in English and an equivalent paragraph in another language, you've diluted the effect of any keyword phrases in that English paragraph. If you have a heading line in English and a second one in another language, perhaps you've lost the opportunity to have a second English phrase as that second heading.
Both SEO and content management/copywriting in general are exercises in balancing many factors. There's not much about which you can say "this has no effect;" you have to consider how much effect each element will have and how that balances against the whole. Sorry it's not a simple answer, but there isn't one!
Specializing in SEO and PPC management.