I just found out that OLX company (something like eBay in Poland) 8th time does "charity clicking action" for dogs in shelters.
People choose a dog they want to "feed" and click it. A person can click each and every day. When dog gets 100% clicks OLX buys 20kg dog food for the shelter.
It's really easy and fun way of helping - if you feel like charity clicking you can find it here, go and click some food for homeless dogs - it costs nothing!
The website is only in polish, but it's quite self explenatory - on the left you have most fed dogs list and on the right least fed, you choose one dog and click. You can come back and feed it every day if you feel so.