Selected answers from the Dumb SEO Questions G+ community.
Steve Gerencser: 1. Your rankings may be affected if the other site is better than yours and simply outranks you. You need to ask them to take it down or, depending where you live, file a copyright claim.
2. There is no penalty for duplicate content. You simply don`t rank well if they declare you the duplicate.
Giannis Hadj: But isnt the first blog that puts the content up the original one?
Steve Gerencser: Not always. Google does not crawl and index every website every day. If they crawl your site once a week and their every day Google could see there`s first. One thing that can help you is to ping Google when you post and get a link or two.pointed to it to help Google know you have a new post.
Alan Bleiweiss: Submitting a Google removal request to Google works most of the time if the site itself fails to remove the scraped copy.
Casey Markee: In your case Giannis, your best recourse is a DMCA Removal Request, and you do that from your dashboard here:
If your request is found to be valid, Google is extremely fast in acting on these. The average is around 6 hours.
Al Jones: DMCA works. Google will be able to check your page first publish date against their and they`ll be able to tell that you are the owner. I know this because we had someone complain about an article we wrote claiming to be theirs. Google was able to tell that the article in question was 100% ours and asked them to remove our copy (verbatim) they had on their site. Yup, some will steal your copy then go and claim its theirs!
Doc Sheldon: As others have said, a DMCA to Google should remedy the issue fairly quickly. However, it`s also worth noting that your original question as to whether or not Google might penalize your blog is technically not an issue, since there is no such thing as a "penalty" for duplicate content.
Bill Slawski: I`ve written the host of sites that have copied my content and told them that the site they are hosting infringed my copyright when that happens, copying the site owner on a request to have my content removed from their site. It has resulted in the copier removing my content every time I have requested that; they haven`t always liked it, but they have removed it.