Google displays targeted ads alongside your messages in Gmail. I regularly get automated notifications from Facebook whenever someone posts me a message.

Jenny wrote something on your Wall.

To see what Jenny wrote, follow the link below:
http://url.com/xyz#wall

Thanks,
The Facebook Team

In the absence of context, this is Google Adsense’s best attempt at responding to such emails:

Berlin Wall?!

It’s the scattergun approach. I guess they’re hoping something might stick.