Is it ok to add keywords on the footer of the website?

Is it ok to add keywords on the footer of the website?
I have seen a few of websites with its footer stuffed with keywords and they have got good positions for those keywords..would like to know is it the right way for optimizing the keywords?

If website is thematic, yes its best way to add anchor text, link in website footer tag.

"Keyword stuffing" refers to the practice of loading a webpage with keywords or numbers in an attempt to manipulate a site's ranking in Google search results. Often these keywords appear in a list or group, or out of context (not as natural prose). Filling pages with keywords or numbers results in a negative user experience, and can harm your site's ranking. Focus on creating useful, information-rich content that uses keywords appropriately and in context.

Yes, keyword with anchor link, It's a best way to get traffic & backlinks from all pages of websites.