Well, it was her third appearance. Last year she appeared as Oswin Oswald, junior entertainments officer on the starship Alaska in Asylum of the Daleks - later revealed to have been turned into a Dalek herself, and later on as Clara Oswin Oswald, Victorian barmaid and governess in The Snowmen, which saw the return of the Great Intelligence - also behind the plot last Saturday.
A few things were noticeable. Firstly, Oswin was a computer whizz, able to hack into the Daleks' path web. And the Doctor tells her that the Daleks converted her because she was a genius, and the Daleks need geniuses.
A genius, eh?
Is the Doctor saying the Daleks wanted her because she has a great intelligence?
And that the Daleks need Great Intelligences?
In last week's episode, Alexei notes that Clara is:
Very clever, but no computer skills.
And Miss Kizlet responds:
Upload her anyway, splice her a computer skills package.
A bit later Kizlet states what they do:
We're preserving living minds, in permanent form, in the data cloud. It's like immortality - only fatal.
Bear in mind, from what we know from The Abominable Snowmen and The Web of Fear, the Great Intelligence is non-corporeal.
After the Doctor manages to download Clara from the data cloud, he explains the situation:
There's something in the Wi-Fi. OK, this whole world is swimming in Wi-Fi. We're living in a Wi-Fi soup. Suppose something got inside it. Suppose there was something living in the Wi-Fi, harvesting human minds, extracting them. Imagine that. Human souls trapped like flies in the World Wide Web, stuck for ever, crying out for help. - which Clara compares to Twitter!
Clara keeps her impressive computer knowledge after being downloaded again. But what if she wasn't fully downloaded? Or what if she were copied in the data cloud? Is that what explains Coleman's two previous experiences?