Hello,
I'm new here so I hope this is the right place to post this. I've enjoyed reading about theories and such but there's one thing me and my sister came up with.
This series has had a theme about hosting and cloning, any threat that the Dr and Donna have had to face appear to have to live inside a human body to exsist. There hasn't been any old enemies (until last night when the Daleks returned) prominent in this series and even the Sontarans used the ATMOS as a host for the poison to be released and they also cloned Martha.
It makes me wonder if Donna is indeed a host to something much bigger, what with the references to something being on her back. If you remember, at the end of The Runaway Bride, The Doctor wanted Donna to go with him but she refused, so why was it so important that she spent such a long time tracking him down? I know we think it was because her life seemed meaningless, but I have a feeling there is something else there. It feels like she's been taking him to all these places in time for a reason.
Donna also keeps refering to the word 'Temp' which means Time in Latin.
Anyway, these are our theories and if anyone else thinks this maybe a pattern then do say so! I'd be interested in what you all think.
AJ