It took some time before I desided to share that one. On one hand, spam is BAD. On the other, it is not exactly spam, but rather an elaborated trap... Well, judge for yourself
First of all, about the target audience. After asking 14 people at work - all of them are software developers and I assure you, advanced ones - I found that only three of them have recognized the word "Bitcoin", and none was able to provide solid explanations - or any explanations at all.
Which means, Bitcoin needs to be promoted.
So how do we approach promoting the thing, if we know the programmers are a target audience? We send them spam... No, stop! Cancel this!
We cheat, instead.
First of all, I have created a "shareware directory" site (nothing fancy, here: soft.snowcron.com). A very basic site, really, though it has all - again, basic - functionality one would expect. A week of work, no sweat.
Then I did some basic (again - basic!) promotion tricks. As one would expect, it ended up on Google's first page on "shareware directory" search.
Then, the site was discovered by automatic submission bots
I didn't do anything! But now (2 months later) I have about 10,000 entries in the database, thanks to robots.
And - did I mention the submission form? It has an "e.mail" field in it.
So, every time I am getting a software info submitted to the database, the author of that software gets (and this is not spam anymore!) a "thank you" email.
Which, pretty much, says, that "as an author of a computer program, you might be interested in our Bitcoin Store Engine, that makes online software sales easier".
So, 10,000 (a bit less, as robots tend to do multiple submissions) people learned about the Bitcoin.