Some of the world's 'stranger' dating sites include one for dating imprisoned women and so-called 'furries'.
'Women Behind Bars' is a dating website designed for people looking for a friend or pen pal of someone in prison.
The website states: "We help connect people with women who are in prison, allowing you to instantly become a pen pal to prisoners. You will definitely meet inmates that seek pen pals for a variety of reasons.
They may want a mentor, friend, partner, or someone to talk to."
The site advertised people becoming a "ray of hope" for the prisoners inside and providing them with the emotional support that may help them rebuild their lives after they leave jail.
They added: "Meet inmates that want to do their time and come out of prison with a new perspective on life. They do not want to return to their old habits and end up back in prison.
"Unfortunately, prisoners do not always have access to the resources they need. These inmates may not have someone who can honestly listen to their concerns."
Confusingly, the site separates the inmates by their ethnicity and age group and lists the interested inmates with a small fee attached to gain the details of how to write to them.
One prisoner inspiringly told her story on the site and said she is "currently attending different programs trying to get tools for a better life and understanding" while "seeking new friends."
Another said: "My goal is to find love, not hatred, and to go back to school for psychology and a reach-out program."
Apps and dating sites can be well specialised to the tastes of people all over the world.
FurryMate is designed for people with an interest in animals with human characteristics.
It is often wrongly suggested that all furries are interested in sexual fetishes involving animals.
Sexual activities like this do exist, known as 'yiffing', but are only part of the furry subculture for some followers.
Despite this, a study at Furry Fiesta 2013 discovered that 96.3% of males and 78.3% of females ones reported viewing furry pornography.
Other sites include ones designed purely for metal music lovers, clowns, millionaires and even people with similar food allergies.
It may not be so strange after all, plenty of sites can match people based on their interests and passions.
Relationship experts at Marriage.com said: "Having shared interests is a great start to a healthy relationship.
You and your partner can already say, 'we have so much in common,' and build on your love from there.
"When you have a lot in common with your spouse, you are sure to have a fun relationship. Having hobbies to do as a couple also creates a support system and a sense of teamwork in your love."
