Four Major Changes happened here. One for better design, two for making a few more million dollars online, and three for more blog exposure (marketing), so I get a couple quadrillion more welcome guests each day.
In my opinion the most important part about these services is that they enable you to share your photos more for free, but all of these services will get you paid by sharing your images and photos and why not? The people who we most currently host our images on make money from our hard work, so why shouldn't we too? They all also offer interesting communities to take part in as well if you choose.