Have been reading about Toutapp - a service that can be used to reveal when you've read an email or clicked a link. A marketing department's dream and a privacy nightmare. Loads of stuff online about how it works (embeds an invisible unique image into an email sent to you) but nothing I can find about how to block it. OK - I can turn off images in email - but I'd prefer not to as many emails have legit images I want to see. I've blocked outgoing connections to toutapp.com - but will this do the trick? Has anyone come across this service?