The "Privacy" page gives a hint. It gives a contact address of "contact@ymal.io". "ymal.io" just redirects back to "taste.io". But WHOIS gives some info for "ymal.io". It's registered to [redacted].
That location is a 5-story building, but the most likely location is Spark Labs, which is a co-working space.[1] $550 a month for a desk. And, yes, "ymal.io" is listed as a member of Spark Labs.[2] So, if you need to find them, that's where to look.
[1] http://www.desksurfing.net/desks/1045-spark-labs [2] http://spark-labs.co/members/
If they are really hosted in Sweden, does the collected data is under Swedish law and not US as mentioned on privacy page ?
"In addition, all sensitive/credit information you supply is encrypted via Secure Socket Layer (SSL) technology.
We implement a variety of security measures when a user enters, submits, or accesses their information to maintain the safety of your personal information."
I really like the service, but it's free to get https setup and takes just about 0 effort thanks to letsencrypt.
But :
"About us" (http://www.taste.io/about): There is nothing about you...
You ask people for their names, email addresses and/or to link to their facebook accounts but you don't return the courtesy of identifying yourself or your company.
You make some promises and cite some laws about privacy (http://www.taste.io/privacy-policy) but if you don't say who you are, we can't even be sure that those apply to you...