I have seen the question bounce around asking why a spammer would bother to send an email to someone that appears to have only one line of text. Sometimes even just one line of gibberish text.
There are two main reasons that I can think of (of course, since I am not a spammer I don’t really know):
1) They are actually also sending some sort of hidden attachment. Anything malicious has to be actually opened and run by you, clicked on or double clicked. So for the most part you aren’t in any sort of danger.
2) They are just trying to get some legitimate addresses. They are going to just take off the list anything that bounces and assume all the others made it to a legitimate address.
Now there are some email spam filtering systems that will bounce back obvious spam right away so that they think it is just bounces. This may help to keep you off these lists as well as make it so it never arrives in your email box in the first place.
Since this is my blog, I get to know offer our 30 day free trial of our spam solution as we do this.