Tinder Best Opening Messages Tinder is an online dating site. However, unlike other dating sites, Tinder does not do matches based on mathematical logic. Other dating websites actually try very hard to make their matches transform into a marriage, however, with Tinder the end result is not necessarily marriage. Dating is more of a casual nature. For the most part, people join Tinder to hook up, basically because matches are based on photos. The key when using Tinder is to ensure that you make a great first impression and the only way to do this is to send a good opening line or message to your match.