If you're taking photos with facebook or flickr as the only location of the end-product, you don't need a DSLR.
Sure you don't NEED a DSLR for Facebook pictures, sort of like you don't NEED electricity to survive, however I can always tell the difference. Compare side-by-side a 5D3+85MM 1.2L vs an iPhone, and even if the pic is downsized to web quality through facebook, you will see a massive difference.
Ditto. Everyone is motivated and driven by different needs and motivations and then they grow. Don't rain on someone's parade just because they use a certain camera or post to a certain site. The U.S. Whitehouse uses Flickr for Pete's sake!
(Ha, ha, get it?) I for one am more embarassed about how much I've spent on my gear than what I haven't spent. If I make great pictures at a wedding with my Rebel and the paid pro uses a 1D series, does that mean my pictures automatically suck? Or do they just suck after I post them on facebook? Facebook is simply a tool for sharing. It doesn't dictate anything other than the desire to share with others. It certainly doesn't dictate what camera should be used.
I don't NEED 90% of the stuff I have. I made great pictures for years with various P&S cameras and a film Rebel that everyone enjoyed. Now I feel I've grown and I prefer the DSLR. But the best camera is still the one you actually use and have with you.