This specific file format ( DVDRip_XviD ) and naming convention are typical of old-school or warez forums (like eMule or BitTorrent sites). Context for this Episode
In the context of the Italian file-sharing communities (like DDLVillage or TNT Village ), a "useful post" usually meant: Lost_2x04_Tutti_Odiano_Hugo_ITA_DVDRip_XviD-tri...
If you are looking for information about this specific episode or why it was considered a "useful post" in a forum context, This specific file format ( DVDRip_XviD ) and