| 1:56 pm on Dec 2, 2013 (gmt 0)|
As a straight answer the title is the most important. Keywords meta is not used and the description does not affect the SERPs.
Slow sites [mattcutts.com...]
| 4:03 pm on Dec 2, 2013 (gmt 0)|
Here's your answer: https://support.google.com/webmasters/answer/79812
I don't even really use meta tags anymore. No keywords, no description due to the nature of my content. The odd time I will use the description one if the page lends itself well to that.
| 5:07 pm on Dec 2, 2013 (gmt 0)|
Search engines expect to find a meta description. WMT complains if there isn't one, or if it's shorter than some arbitrary value (I think it's 50 for google, 30 or 35 for bing). Or longer.
If you don't have a meta charset I devoutly hope you've got a global setting somewhere ;)
| 10:16 pm on Dec 3, 2013 (gmt 0)|
OK I have that one tag for utf-8 in an include file. But I send it through .htaccess headers anyway.
| 12:15 am on Jan 3, 2014 (gmt 0)|
Just to clarify, the title tag is NOT a meta tag. That being said, there are no meta tags that positively effect SEO. The title tag DOES.
| 12:24 am on Jan 3, 2014 (gmt 0)|
facebook will use the meta-description tag for a shared link's description when no Open Graph description tag is present. I use meta description in hopes it's used by Google, it does get used much more by Bing and other SE's.
facebook will display 3 lines of description text, which might be upwards of 200 characters before showing the "More..." link. Clicking will show the rest up to 299 characters.
| 12:32 am on Jan 3, 2014 (gmt 0)|
Incidentally, I was wrong up above. g### complains if your meta description is too short, but doesn't say anything if it's absent entirely.