I got a couple of emails this morning inviting me to become a mystery shopper and earn at least €200 "per venture". They make it sound like you just dine out and fill out a report and get paid. This was done last year in a Sunday newspaper ad as well (until I rang a journalist in the paper and pointed out it was a scam, they were quite embarrassed!) They’ll look for a few basic details to build confidence and you can imagine where it goes from there. While there are many genuine research companies that use mystery shoppers, they don’t invite complete strangers by mass email to join them. The reply address implies it is linked to http://www.mysteryshopper.ie but when you go to that it is a single page saying you must upload your website to see it!
I deliberately have a dummy format of an email address that if anyone uses, I know it’s a scam so I get to spot these quite easily. Be warned