A former editor of the Greenwood Tree met his wife while doing family history; I once had a box of chocolates sent me from Kansas City - see 'choc or bloc' which I'll post some time. My longest-running family history partnership goes back to 1994 and has seen us through changes in life circumstances, several trips to the States, and many a curry. One gets dozens of contacts from people all the time, through Ancestry or Genes Reunited. How on earth do you decide 'how far to go'. I'm not suggested a church, but a marriage of ideas can prove pretty compelling.
I guess I'm looking for staying power. I like to include enough information in my first message (or first reply) to get the other person interested, if they are a family historian; and to encourage them to open up a bit, if they are not. But I hold back. Those contacts who demand 'all my information' I dismiss as one-night emailers, and probably our relationship isn't going anywhere.
I'm also looking for eye contact: very hard through email. The closest I can get is a touch of honesty, something you wouldn't tell the mailman: 'I'm away for two weeks; I'm at O'Hare; my daughter was very excited to hear about your message; I wish you could have met my father'. In contrast, worrying signs are easily elicited over your second date, or message: 'I found all the data online and have no information beyond that; I'm not related to these people they are just on my tree; I'm confused they had the same name could a brother marry a sister?'
Most of the time, the second message never comes, and we know it was a fleeting moment. Peter Calver at LostCousins won't allow you to exchange information unless the recipient has the courtesy to acknowledge your first enquiry.
It's worth being patient with newbies, or to borrow from the dating world, 'fresh meat'. They may bungle the facts, but with your experience you should be able to set them straight. A lady asked if her grandmother's relatives were related to her? Another had incorrect baptismal records for our John Purton, but was happy to acknowledge she might be wrong, a charming touch and so rarely seen.
The more people adding good data to sites like Ancestry, the fewer brickwalls we'll have in our research, particularly going 'downhill' from the past to the present. Oftentimes, it is newer researchers who are able to add this information. (I have written earlier about the strength of weak connections.)