Both. Usually though, I access Forumer.io through my HP Laptop as it's quicker to touch type. Furthermore, my PC screen is bigger enough for me to see without my eyes being strained from writing content on an iPhone 5.
I usually use my desktop when I access anything online. Sometimes I use my phone but mainly my desktop computer. I find it's faster and easier to browse around and you can have more windows open if your visiting various sites at one time.