Any company has a choice about how they send their brand-message to the world. How will they communicate with users, and what will their message be? In my opinion, that communication falls somewhere on a binary between spam and sharing, and I really love when it falls closer to the latter.
My current favorite freebie is BrowserQuest, a retro-style MMO browser game recently released (for free!) by Mozilla and Little Workshop. They could have taken out banner ad spaces to say “HTML5 Rocks!” or “Mozilla is cool”, and I would have completely ignored them. Instead, they created a little gem of a game, and it has won me over.
Here is the link to play BrowserQuest. Enjoy a few minutes (or a few hours) of HTML5 powered fun!
Making a completely free game is an extreme example of sharing great things with your users. Another way of sharing is by actually giving away some portion of your product, and this can take any number of forms.