Here I am listing some sites where you can leave a comment or point a link to your blog.
site:flickr.com “your keyword”
site:blogspot.com “your keyword”
site:hubpages.com “your keyword”
“powered by WordPress” your keyword
Another important strategy to find good posts is Google Alerts. You got to subscribe your keywords to Google Alerts. Every day Google will send you the list of articles, blogs, websites that contained your keywords, all you gotta do is review the blog posts and comment on it. Very Simple!