Addi, no worries at all. I was just curious if you had read or heard something I hadn't.
As has been better explained already here, than I could, Dr Who does follow a more standard US writing system than the traditional UK television format does (I'm not sure if this was because it had more episodes than the average UK show does, if RTD didn't want to have to write each episode the way he did for the much shorter Queer as Folk, if his admitted love for Buffy/Angel caused him to want to try that model, or *what*, but...) though I think it still has a smaller writing team.
I know that with the US it very much depends on the showrunner/headwriter as well. Some are notorious for doing a final rewrite, often uncredited of every script (Weiner at Mad Men usually takes co-writing credit because, as he has freely admits he thinks he deserves it). I believe Sorkin tends to actually write out every final script himself, but he still bounes ideas with a writing team.
And it gets more fuzzy--Angel, Firefly, Dollhouse were all considered Joss Whedon shows, and for obvious reason as his control and stamp is all over them and he created, or co-created them. But I think Whedon fans (and I'm one) tend to sometimes not realize that for the majority of them he wasn't actually the showrunner, taking a more overseeing/consulting role partly out of being so busy (in fact when he scripted the occasional episode of Angel in its final years himself, I found them to oddly feel kinda out of tone with the show).
(GQ did an interesting, but brief, discussion with Weiner about Mad Men, Milch about Dead Wood, etc, and Vince Gilligan about Breaking Bad and their individual writer's room experiences. Of course, as Plum said about UK shows, the same is true about US Cable shows--due to less network interference, and a smaller number of episodes to focus on, the showrunner/headwriter of a US cable show has more overall control and, for lack of a real word "auteurship" over their show than one would have on network US tv.
http://www.gq.com/entertainment/movies-and-tv/201206/roundtable-discussion-matthew-weiner-vince-gilligan-david-milch )
I admit I find the whole process interesting--and the differences in the process (in the UK traditionally sitcoms were written, as well, by one writer--the creator--though he or she might have others on their staff, probably another reason for much lower episode counts. ie Coupling was basically Steven Moffat's Coupling.)
When there are different writers, like with Who and Torchwood and the majority of American shows (network especially but also cable), geeky fans like myself do start to notice which writer (who, in a way, is maybe more of a scripter taking ideas from the headwriter, and writing room discussions, and implementing them) writes episodes we prefer, which may write ones where people feel out of character, etc. I believe there's some odd union law in the US too where for each season of tv they have to hire an outside writer for one or two episodes--for some reason--sometimes these people then join the writing staff in later seasons, or not...
But as Plum said, even when they do special episodes with an invited guest 'star' writer (older examples would be Stephen King on X-Files), the headwriter still has to make sure that certainly plot points are made (if the show is in any way serialized, especially), oversee that nothing grossly out of character is done, etc.
While it's a different process again writing a daytime soap opera, when I was at my most fanatical watching All My Children, even there fans would notice which names would pop up when an episode would have better or more clever dialogue, etc (in that case, because they have to churn out so much product, the writing room has even more structure with breakdown writers taking the headwriter's story plans and shaping them into weekly and then daily episodes and then different teams being sent out those breakdowns to write the actual script--some of the better headwriters would then oversea and change aspects of each script, but honestly with daytime soaps I think most simply didn't have the time or patience).
Bobs, I suspect, but I have no way of knowing that the Pond/Song connection is all Moffat. It just *feels* more like Moffat's style more to me--if that's a good reason at all... (and honestly I liked the reveal, but I find that Moffat's handling of the major story arcs can often get unruly and too messy--even if he has been more adventurous with them than RTD was, IMHO).