But if you want a step-by-step process to see if yours is, check out this Brandon Wason post. I think #3 is by far the most egregious violation of the blogger's code of honor:
Truncated RSS. Most blogging software packages allow the administrator to post their RSS feeds as summaries instead of displaying the entire content of the post. This usually just means that they show the first fifty words or so of the post. As far as I understand it, by truncating posts in the RSS feed the blogger is forcing their reader to visit their site. This, of course, is great for the blogger, but a tad annoying for people reading their blog through RSS aggregators. Perhaps their is a legitimate reason for syndicating your blog posts in a mutilated form. I just don’t know of one.