Bubble is a great tool for duplicating functionality of existing websites like twitter, etc.
Does anyone every worry about copyright issues if someone released a website that is extremely similar to an existing website?
Can only speak regarding Canadian Law; Copyright is just that, you can not take an original and copy it. However; if you create it from scratch and do not steal the code it can look the same. (Notwithsanding patent law). Since the code is different (which is what is copyrighted) you are not making a copy. BUT… back to patent law. If the functionality is patented that is a whole different matter. You can patent how things work but not necessarily the code underneath. So if I write a program that does a function and patent the function (if sufficiently unique) even though you are not copying the code you can not copy the functionality. Facebook for example has a number of patents. As an intresting gotcha… under Canadian law if you market a product (lets say functionality) to the public without a patent then you can never patent it. There is a grace period but if you wait too long you miss the boat. I would worry more about patents… since using Bubble you actually don’t own the code since you do not create the code. This does create an intresting question regarding IP rights to an app created using Bubble?
John
Good info! And Canadian law was Exactly what I was looking for.
By the way, just because you could make it look exactly the same it would be unethical to do so and actually bad business. It is much better to be different, since of course your product is far superior to the older one. 
Agreed…