I only just started playing a couple months back, but I use dandwiki for quick information before checking out the phb or google.
For me I think the big things are the distinction between SRD content and homebrew. I can read through a section on my phone and get pretty excited to then notice that its all a homebrew rule.
*I don't know how others feel, but for me, it is much easier to read a homebrew link then a srd link. I think the reason is the color difference kinda throws me off.