As long as someone has not copied anything substantial from your work, they can get away with it, so before you claim infringement, you should have sufficient proof that your work was reproduced and the copied work is taken or copied from your original piece.
One of the factors considered in court for copyright infringement is the quality and quantity of the work that is copied. For example, if a large proportion of your original piece has been copied, but the copied work is significantly unoriginal, copyright infringement might not be found, but if a small proportion of your work is copied, but the copied material is very similar to your copyrighted material, then infringement can be found. Any work reproduced for reporting, research, in the public interest, or books and newspapers for private use may not be considered copyright infringement.