Ezine's policy to submit is that you don't require anyone to leave links in your articles. In other words, the articles are free to do what ever you want to do with them. However, that is not the same policy for all article "hubs". Read the TOS. In fact, if you find an article on one site that you really like, but there are a bunch of strings attached, I suggest you shop around, chances are that you will find that very same article published on a not so restricted site as well.