If you advertise that you lead to a marrige then its not about you getting married today, its that x people who use site y get married every day. Of course there is no garantee that the marrige had anything to do with the site. If person x and y are on a dating site, there is no reason to assume that it MUST be true that if x and y met/get merried it is due to the site. They could meet outside. With 20 million accounts it is VERY likely that you got married to someone with an account on that site.
I like the corelation you can build from the site: By giving you bad matches to increase business, each person looking gets less likely to find someone because they have to send so many emails. Note that the 30% chance to get a response * 1/30 chance that an account is not active != 1/100 chance of a response. The 30% chance to get a response can already take into account that a bunch of people may not be active.
You can play with the numbers. I think the final guesses are not that accurate, but it does put things into perspective regarding the marketing numbers.
I like the corelation you can build from the site: By giving you bad matches to increase business, each person looking gets less likely to find someone because they have to send so many emails. Note that the 30% chance to get a response * 1/30 chance that an account is not active != 1/100 chance of a response. The 30% chance to get a response can already take into account that a bunch of people may not be active.
You can play with the numbers. I think the final guesses are not that accurate, but it does put things into perspective regarding the marketing numbers.