Larry -
In Pinterest, the little heart button is just like the Facebook "Like" icon. (But they had to be different, so it's a heart, meaning you love it. But not in the till-death-do-us-part way.)
Here's a link on how you can like other people's pins:
https://en.help.pinterest.com/entries/22980372-Pins-and-likes#like
From Pinterest:
What's a like? (The Heart Shaped Thing)
Liking a pin adds the pin to your profile’s likes section rather than a specific board.
To like a pin, hover over the pin and click on the heart icon in the top right corner.
What's a pin?
A pin is an image or video you add to Pinterest that leads back to the site where it was found. You can pin anything you find on Pinterest or around the web.
Having lots and lots of people pin a product on your website, or an image or video on your page adds to it's social media profile, and should help with both consumer engagement and possibly rankings.
Hope this helps!
-- Jeff