You can reject the calls with one touch on smart phones, but if you live in a country where you keep getting pesky marketing calls throughout the day, here is what may help you.

If you get those Junk calls from a specific number or numbers, save it as the name Junk (or anything you prefer). Once saved, assign them BLANK ringtones. So the phone would ring, but not ring, hence it is automatically ignored.

    Download the following blank.zip file.

    Extract the Blank-WP7.mp3 if you use WP7 or Blank-iPhone.m4r if you use an iPhone.
    Drop the MP3 file to Zune (WP7) or M4R file to iTunes (iPhone)
    Once dropped, sync as usual.
    Now, edit your contact called Junk, and specify this Blank ringtone.

As they say… silence is bliss! Enjoy it.

Until next time,
Rahul