"Hearting" something on Pixel Scrapper is just like "liking" things on other sites, like Facebook, or Pinterest: it's a way to show your support for things that you like or agree with.
Vote for the features they would most like to see implemented by hearting those posts. The feature requests with the most hearts are going to be the ones that go to the top of my to do list...
To heart a topic, just click on the topic from the topics list within, and click on the "heart this" button:
You can also now see the number of hearts that each topic has received when browsing the forums, and sort by that number if you'd like: