What I have done before (if you are away somewhere) is to go to the dive shop, do the first day diving with the centre, It may be a bit more expensive, but you will get to know the area better. I find often on these days that you meet people while out.
After spending a day on a boat with someone I think you will get a better feel for them than through an online match-maker.
I too have few friends who dive and this is a problem. Although if you put the time into getting to know people then it can be rewarding and a nice way to share advice, information and experiences.