Postcrossing extravaganza

Postcrossing has gone crazy this week -- previously I thought I understood that in order to receive a postcard you had to send one, but in one week alone I have received three different postcards without having sent any more. I have one all written and ready to send to Finland (yes, Finland, again) this week -- but have no idea why I have been getting cards without sending any. Not that I'm complaining, I like getting post.
This first card is from Doris in Austria. She lives in the town of Wiener Neustadt, which she tells me is located about 50km south of Vienna. She also tells me that she would rather live in Antwerp, in Belgium. I don't know why, she doesn't elaborate on it...

My second postcard comes from Finland, from the town of Lappeenranta, a city of aprox. 58,000 people close to the Russia border where the sender lives with her boyfriend and their three cats.

The front of the card reads "Everyday 160 million cards are sent. This one is for you!" which I think is a very nice sentiment. I don't know if that figure is worldwide or just for Finland -- it seems that sending postcards is a very popular pasttime for the Finnish.

My third postcard of the week came all the way from Germany. The sender Stefanie doesn't say what town she lives in, and doesn't offer any insights into what is quite an unusual looking card. The picture seems to show a road accident, and I'd like to point out that the writing says "HILF" and not MILF. If any German speakers can offer an explanation as to what this means, and what the cars is saying, I'd be grateful. Maybe it's part of a campaign for road safety? Either, Stefanie is 24 and makes polite conversation about the weather, before mentioning that her baby son learned to walk a few weeks ago and "is now exploring the world". It's quite a random bit of information to drop in, after expressing her hopes that the weather is nice in England.

International readers -- which is pretty much everyone who comes here: is this a widely-recognised piece of diplomacy? Are you taught that if you have to make polite conversation with an Englishman, you should mention the weather?

Stefanie seems particularly keen for people to visit the website for her son, since she includes a link to it on my postcard and mentions it in her postcrossing profile. However, I'm not sure she would want me linking to it from here.

I might start scanning in the cards I send, too -- I think the general consensus is the more pictures around here, the better.