3D printing is gaining more and more momentum to build customized product in a wide variety of fields. We conduct an exploratory study of Thingiverse, the most popular Website for sharing user-created 3D design files, in order to establish a possible connection with software product line (SPL) engineering. We report on the socio-technical aspects and current practices for modeling variability, implementing variability, configuring and deriving products, and reusing artefacts. We provide hints that SPL-alike techniques are practically used in 3D printing and thus relevant. Finally, we discuss why the customization in the 3D printing field represents a challenging playground for SPL engineering.