If you want to prove that you published a content first, what you have to do is find the dates related to that information from your content and the copies.
These are ways to check that
- FTP upload log.
- First/oldest HTTP transaction involving that content.
- inurl: or site: searches on Google plus the use of "&as_qdr=y20" in the resulting URL.
- Looking for the content on the waybackmachine.
- Check the
Last-Modified header of the page.
- Check the declared publishing date
Method 1 requires that you have a log of the file, which may be difficult unless your hosting company provides that and you keep them. You can always ask for it to the company and hope they have it.
Method 2 is not too difficult, you may have it or at least you may have some data on the hosting provided statistic services they provide, like awstats or similar, just look for a date close to the publishing date.
Method 3 requires that you do a search on Google like
inurl:http://www.example.com/specific_page and once you have the result, add "&as_qdr=y20" to the end of the url and the result would include the publishing date if that happened on the last 20 years.
- go to Google
- in the search box type
- in the resulting URL, add "&as_qdr=y20" so it will change from
Method 4 is very simple, go to the Way Back Machine, type the URL that you are looking for and check for the oldest version they have.
Method 5 may not be present or show today's date if the document is generated on the server, like with PHP, ASP, etc.
Method 6 is not conclusive since anybody can post anything, but if they published a date that is more recent than yours, you can always use that against the stealer. If they use a CMS, or blog, or any other system that uses dates on the URL, you can always check that URl, which is more conclusive than the published date on the content of the page. Even if they use pretty URLs, you can try to reach the content using date patterns for the most common systems.
You should use all of them, if possible, to be sure and to gather as much information as you can.
Method 3 also may not provide information about the date, that happens with some sites. I can't tell why some sites are shown with the publishing information and some don't, I have some ideas, but this is no place for those speculations.
Method 3 and 4 depend on the time the page was crawled which is not conclusive, but if it happened, then you have a proof.