In conclusion, here's what you should remember about giving out free downloads with your music.
1. Personally, I'd only have select songs available for free download. If you think all your music should be free, so will your fans!
2. If you do want to have a plethora of free downloads, use Click.dj or a similar service to at the very least get a SoundCloud follow from the fans.
3. Remember that telling people your music is on iTunes isn't SELLING it to them. All that does is make them aware they can buy it. Big difference.
4. You really want to get an email address if you can in exchange for free downloads. However, this takes some work to set up efficiently (much more than I can describe in a blog post).
5. The goal is to get SOMETHING from your listener so you'll be able to keep in touch with them. If they download your songs without following you on some platform, they won't necessarily be aware of when your new songs are being released.
Make it as easy as possible for people to find your music, but be smart about it.