I live in a smaller city, and it regularly takes a while for location based web stuff to catch on around here. I sign up for them, but since thresholds of usefulness take a while to be met, I completely forget about the service -- then one day I'll hear about it from someone local, decide to give it a try, and rediscover my existing account. As such I like the occasional email reminding me of the existence of these things. Preferably something in the form of:
Hey, thanks for signing up. We are still waiting for more people in your area to sign up, currently there are only n users, which doesn't quite meet our threshold[1]. We just wanted you to know we haven't forgotten about you. If you have any suggestions on how to get more users near you, let us know!
[1] alternately: n other people are using it, spread the word and get even more!
A frequency of once a week on that seems pretty reasonable, rather than once a day. In this particular situation I think a balance between "forever alone" spam and "hey, we still got your back" emails is a nice goal.
3) We've given that some thought and we've decided against sending emails saying you're FOREVER ALONE (btw if you DO want to see it, head over to /rank-people to see how many potential matches you have. However, your insight has shown us that thought alone is not useful in making decisions. On this, I'd like a show of hands who think that it's a good idea to send update emails to tell you that the system is working on finding matches for you?
4) Haha, we've actually ran into this problem in our 2 week beta test. We're currently working on a system to incentivize users to host dinners.
5) Yes we have a post-facto rating system in place. It has questions about security, friendliness, our match qualities... In fact I can tell you there is a system that is pretty much like Xbox's TruSkill that is powering the rating system, except with more fun stuff.
[1]http://blog.strangersfordinner.com/2012/05/out-of-the-way-1-...