I used to live with a designer who independently came up with many ideas that we ended up seeing show up over the years. He had come up with this video idea of people's thoughts bubbling over their heads, nothing special, and in the short term a Toronto Dominion bank commercial had the exact same thing. Many designers read/resource all the same sites, it's no wonder there are similar designs. I figure this explains some of the "less compelling" duplicates, perhaps it was just people thinking along the same lines?
A couple of the coffee cups might not be direct copies, but the majority of them clearly are. The proportions and shapes are all nearly identical.
If you described this logo to ten random web designers and asked them to draw what you described, you would end up with ten considerably different looking cups of coffee. With these logos, almost all of the coffee cups are the same.
The coffee cup: Many of the cups are identical. Not similar, but identical. I think that different designers would sketch cups that are very nearly the same, but I find it hard to accept that they'd create identical cups. Using steam for F is an idea that many people would arrive at, but these examples are again identical spirals and lengths. (The coffee bean example in the lower right corner stands out because it's obviously nothing like the logo)
