Say I write an article for a keyword at ezine and it ranks in the top few. Does this directly affect the ranking of your site which the article links to? Also, is writing and posting keyword specific articles on your own site better for bringing in traffic than using ezine or something like that? How do you promote an article on your site/is it worth it?
Yes, if you have a 100 or so backlinks that rank high for that keyword. Do both, never rely on just search engines and never just rely on article directories.