Anyone knows whats the exact max number of characters for meta tag keywords, descriptions and title for Google and Yahoo?
If you're worried about the max number of characters you're not focusing the keywords for each page. Pick a small list of keywords you're trying to target and get variations of them on the various tags. If you're getting too many then you should break up your pages into smaller themes.
First, the description should be geared towards the visitors and not search engines; it's 138 characters including spaces. Make the description the "executive summary" of your web page. Meta keywords isn't used by search engines anymore due to massive abuse in the past, so just provide 5 to 10 simple keywords if you really feel like adding more code to your header!
I started a new site about 4 months ago and I totally eliminated the keyword tag. I just have the title and description. It's been working very well. I personally don't think any search engine uses them anymore. that is however, my opinion.
- Separate phrases in your title with a '|' . Ex. Blue Widgets | Blue Widget Articles | Blue Widget Guide - The Keyword meta tag is hardly even worth the time spent adding it. If you are making all of your pages based off a template, it might be worth it to add some keywords in the template page. If you add a handful of them, it won't hurt, but it probably won't help, either.... at least with the major search engines. It might help a tiny bit with some of the smaller SEs