Automatically login a user via a link

I want to create a personalised invitation website with a poll. I don’t want my invitees to have to enter their name, plus I want to create a personalised touch with their name or maybe even a photo on the invitation. I guess I can do all that using user functionality, but how can I “login” a user by a personal link? Can you provide some pointers please. Thanks!

If I understand you correctly, you don’t even want to log them in automatically, but only to show them contents based on unique URL parameters. So everyone who has the unique link will be able to see the content (not secured at all !!, of course). Am I right?
So create a database collection “Invitees”.
add the relevant data such as name, photo etc. and create a dynamic page based on this collection (ID field). It’ll automatically create a URL for each of them. Then, on the page itself, connect the text and image placeholders to the dynamic dataset fields, and that’s all - you have a url for each of them.

Probably you’re right. Will have to figure out how to make it work with the polls in a decent way.