Maximum number for Meta Keyword for a web Page

I know some bloggers or web developers  may be wondering if there is a limit to the number of keywords they can list in <meta name="Keywords">  

Well, As far as I know there is no technical limit on the tag, but, the keywords placed in that tag should reflect the content of the page they are on.If the keywords placed in your keywords tag aren't used on the page there is no reason to have them in the tag.

Keyword tags are largely ignored by the search engines but if you decide to use the keyword tag keep it focused on the page content, not the entire scope of the site. 

My friend who is a SEO specialist says you can go up to 1000 words in meta keywords. But, He generally practices 25-50 words in Meta keywords whether you use keywords or key phrases. But do make sure they are relevant to your page and appear in page-content in one form or another.

 
Also, Some directories and search engines may refuse your site or a specific page if you overdo it.Most engines don't use the keywords tag at all or only the words that also appear on the page.
 You should Know, that Now-a-days, Meta keywords are loosing their importance with search engines specially with Google. So, Give prime importance to <title>, meta description, <H1> tag, text links etc. rather than focusing on Meta keywords. They add to page-size but are less important as per the search engines are concerned.
  Just think of Meta keywords as an opportunity which you can use to show your future clients. Hence if you have 10 keywords in them and all of those Kw's are in top 10 reflects good on you. But suppose you have 50 keywords in them and only 1 ranks in top 10 not so good. I think you got an idea of what i mean.