Google made historic news yesterday by declaring they do not use the meta keywords tag. Okay, I am being incredibly sarcastic. Google hasn't used the meta keywords tag for an incredibly long time and any "SEO" should know that. So why did Google blog about this, on the record? At least two reasons, (1) people continue to sue over it by claiming copyright infringement and people confuse the meta keywords with the meta description, which Google does recommend to use.
If you want to know which meta tags Google does pay attention to, see this FAQ. Plus, Googler's JohnMu tweeted that Google also does "not adhere to the "revisit-after" meta tag," if you wanted to know.
Finally, here is a video if you don't want to read any of this: