Does sending smtp messages attract spam?

[TheGreenOne]

I rarely use my work email address on the internet.
Up till recently I rarely got spam at work.
Recently I began testing a program to send messages to my customers.
The messages I plan to send are only ones that are requested by the customer, it is not spam.
I am using a free ware smtp program to send the messages.
It is a simple one (I forget the name) I tell it the address, the subject, the mailserver, the body of the message, and the from address then I trigger the send.
I have been testing it by sending myself messages.
Since I began testing it I began to get spam.
Does anyone know if sending messages in this way is less secure than by using a regular email program?
Has anyone else experienced the same correlation between using an smtp control and receiving spam?
Is smtp a spam magnet?

All comments are welcome.

Thanks in advance.

 

[BitFuzzy]

There are several reasons this could be happening.

Someone or yourself signed up for a site membership or email list (these usually result in spam)

A worm on your or someone who has you in their address book could be sending or supplying the sender w/ your addy

But if I'd bet that as soon as you provided the requried information to send your email, and activated it, you sent your address, and perhaps every address in your bulk list to someone else.. Congrats

 

[TheGreenOne]

Thanks for the input.