Long terminal repeat retrotransposons occupy a large portion of genomes in flowering plants. In spite of their abundance, the majority are silenced and rarely transpose. One of the examples of a highly active retrotransposon is Lotus Retrotransposon 1 (LORE1), of the model legume Lotus japonicus (Regel) K. Larsen (syn. Lotus corniculatus L. var. japonicus Regel). LORE1 has several unusual characteristics that are interesting both for studying evolutional genomics and for the use of LORE1 as a genetic tool. In this review, we present the characteristics of LORE1 and discuss the biological significance of LORE1 as a member of chromovirus, a chromodomain containing clade of the Gypsy superfamily. Then we discuss possibilities and methodologies for using endogenous transposable elements as mutagens to generate gene tagging populations in plants.