Being donor-conceived makes family relationships all the more complicated, especially as we move farther into the future. We must distinguish between our full-blooded siblings, our half-siblings we're raised with, our half-siblings from the same donor, our half-siblings raised by our donor, our dads, our fathers, our non-biological paternal relatives and our biological paternal relatives. And this is only a single generation!!
By the time we're grandparents our family trees are going to be so complex that we might not even be able to keep track of all our nieces and nephews!! Especially these donors kids with 10, 20, 30+ siblings!!
So I found out that WolframAlpha (a computational knowledge search engine - basically it calculates or provides information on just about anything!!) has a genealogical relationship calculator. While it is really not able to deal with such complex situations as donor conception currently would allow, it's a really awesome tool to play with for fun or for genealogy purposes!
Basically, you enter the relationship you want to know and it will provide more common names for that relationship (example is cousin's son = first cousin once removed). It also provides how much DNA these two individuals would share, and other bits of information for the curious genealogist.