The site seems to have plagiarized par of rubular.com Note its quick guide: http://imgur.com/vU0fo http://imgur.com/vU0fo And here is Rubular's quick guide: ht

The site seems to have plagiarized par of rubular.com Note its quick guide: http://imgur.com/vU0fo http://imgur.com/vU0fo And here is Rubular's quick guide: http://imgur.com/gJjhM http://imgur.com/gJjhM There are other similarities too. The site also doesn't say what regular expression specification it is using. All this aside, is the website doing any real harm? Probably not. But in my opinion you should at least credit a website if you use things from it. Note: These were just my first impressions. There are numerous ways how this situation could be different than it first seems, and I don't want to condemn anyone unnecessarily.