It's interesting how little value the answers to this question seem to have.
dating/t-shirts - Lots of people date and buy t shirts online. I don't get this.
social or mobile _____ - How long have these been pursued? Most people don't even have smartphones yet and the first and only social thing they use is facebook. Patience.
grocery delivery - I can get groceries delivered in my area (melbourne) by one of several big companies. 10% or 1% of a one of the biggest markets is not failure, is it?
Maybe it's not possible to answer this question in a useful way.
Some of this has to do with how you define success. For dating, in the Quora said someone said "well Grindr is doing well". They have traction, in a niche community (m4m) but I'm not aware of any revenues.
Context is another - online grocery delivery is VERY successful in the UK too - for many reasons including lower car ownership than the US.
You might need to define 'successful' for online grocery in the UK. Ocado is losing money and I doubt that the major supermarket operations are profitable.
I wasn't aware Ocado was loosing money - they were definitely my delivery service of choice when I lived back home in London. I think something similar an independent company based on Whole Foods (rather than Waitrose) -- would be successful here in California.
dating/t-shirts - Lots of people date and buy t shirts online. I don't get this.
social or mobile _____ - How long have these been pursued? Most people don't even have smartphones yet and the first and only social thing they use is facebook. Patience.
grocery delivery - I can get groceries delivered in my area (melbourne) by one of several big companies. 10% or 1% of a one of the biggest markets is not failure, is it?
Maybe it's not possible to answer this question in a useful way.