Sometimes you may feel like your life is pointless. Just as if you were wandering on Earth without really being of any use to anyone. And volunteering when you have depression and/or social phobia is not always an easy task. There are ways to help without making much effort: You can buy your clothes or part of them in charity shops: sometimes they have really nice clothes, they are cheap, and your money helps people in need. Internet is also a great place to help: they are lots of websites where you can raise money for rescued pets, disabled children…just by clicking once a day! (e.g http://www.theanimalrescuesite.com/clickToGive/ars/home).
If you’re suffering from a mental disease and realise that (safe) actions on your body and mind help you relieve the pain, do share them. It may not work on everybody, but someone may read your post and try your tips and feel better (be sure what you propose is healthy!).
Writing a kind comment on the blog of someone who is struggling takes a few seconds, but can cheer them up. If you feel sympathy for them, do write this nice comment. Just: “I hope you get better” or “what you wrote moved me. I wish you the best.” can make them feel a bit better and make them want to hold on.
You can never be useless. If you’re guided by your heart, you will always send away positive energy without even exhausting yourself. It may even help you in the end.