I think the bigger problem is 2.7m * .55 CPA * 7x ltv = a market oppty for THEM of $10.3 million if every bride in America signed up for their service, assuming knot.com and competitors don't try to copy them first. What's worse, they have to re-acquire their user base constantly. Weddings are like apartments or cars... It's totally point of need, and only one or two brands will be on people's minds.

It's unlikely that it's more than $1K for clothes on average (estimate based on: http://www.moneyunder30.com/how-much-average-wedding-cost). So the real market for wedding clothes is under $2.7 Billion.

I'm sure they are going to be going local and adding services soon. That way they can get at the whole 28k. Probably expand to babies and home to keep the customer after the wedding too...