Ask HN: How do I get people to try my (free) service?

http://cansend.com/

I've tried posting a Show HN - got 5 points, 1 new user, some feedback on my site's lack of info.

I've submitted it to the mailchimp integrations directory - got listed but no new users.

I've tried pitching it to startup people I know, website owners - I've tried pitching it at startup meetups, events - people think it's a cool idea but no one to actually try it yet.

I've also tried posting to programming groups, forum software groups...

Would be grateful for any good ideas