If you got an invitation from me to Quechup, ignore it. In fact, I advise you to boycott Quechup altogether.
Unlike other social media sites where, when you sign in, they scan your contacts and ask you which ones you want to invite, Quechup simply invites everyone you ever emailed or from whom you've received an email without asking or even notifying you.
This is so dumb as to be beyond belief. They invited mailing lists, customer support to whom I have contacts, listservers, people I've told to sod off, etc, etc. Whoever designed this system is a moron. And worse than just being a moron, it is making everyone angry, and for good reason.
Some companies deserve the benefit of the doubt for a mistake, but this one doesn't. Quechup belongs in the dustbin of failed startups.
P.S. All mail to me originating from quechup.com is now automatically forwarded to firstname.lastname@example.org .
Update: Quechup decided to get even smarter, and now sends all of the invitations with the email address and reply address of your supposed friend, and removed the word Quechup from the subject line, so that it's harder to automatically spam them back. Hard to believe they aren't doing this on purpose, now.
They also added an "unsubscribe" link to the bottom of their mails, allowing you to opt out of receiving more emails from them. Typical spammer behavior would indicate that this is just one more way of collecting email addresses, but I decided to give it a try, anyway.