Be very, very careful what you put on paper – or on the web. You’d be surprised how files can “get around.” It might not even be the shadchan, but the shadchan’s kid or whoever who has access to the files. And if someone hears something and declines to believe it, the reply, “She wrote it herself,” is hard to meet. And anything that’s on the internet – even if the site is frum – is open to the world forever and ever.
Another disturbing thought: I have known shadchanim who shmooze about their clients, the idea being that if you don’t mention specific names, then it isn’t lashon hara. Unfortunately, sometimes they give details that would make it possible to identify the person if the hearer knows the “client.” This might be less of a problem in a smaller community where everyone knows everyone else anyway, and sees them as whole people rather than just some gossiped-about quirk, but where the families are strangers, it could be fatal. Shadchanim should never, ever talk about their clients in any way, shape or form unless it’s for direct tachlis. It makes for duller conversation, but being a shadchan is in the same league as being a counseling psychologist – what goes in the ears must never come out the mouth. Anything else is an aveirah and a betrayal of trust.