Some are niche-based, so you can meet people with similar interests or backgrounds.
Like a lone wolf trapped on a floating iceberg, how will you ever return to your wolf pack and find a hot wolf-mate to love? When you date a man or a woman, the feely-weelies and sickening lovey-doveyness at…
The difficulty with choosing the dating site for you is getting past the fact that you more or less have to sign up to see what they're like.
Though there are review sites which will give you a feel for what to expect, eg:
However, because it's so easy to sign up, anyone can, so you should expect to have to do a fair degree of sifting to find people like you.
You should also bear in mind: Category two people are generally likely to be better off with solutions where they can be reasonably sure that people they meet are also looking for a serious relationship.