Do meta keywords separated by comma have anty priority system like if any keyword is at first, is much proffered than the second keyword, like this?
The major search engines don't even read them - shove a few in, don't spend more than 10 minutes thinking about them
so, should I forget using meta keywords and focus on make the articles rich based on my niche keywords?
The keywords meta tag is ignored. Use the title tag and meta description. The most important is in the page content, including anchor text. image alt text, body text (heading, paragraphs, etc). This is known as on-page SEO.
Only google ignores the meta keywords. You will just want to add the meta keywords for the sake of completeness and then focus on make the articles rich based on your niche keywords. Do not spend too much time on meta keywords section...
It was a value in early days, but due to its easy manipulation nature, its now being ignored by most of the search engines.
If you are talking about Title tag - then priority system is working for targeting keywords. if you didnt notice then start noticing on keywords which are first on title tag, it will get ranking speedy then other targeted keywords.