[mindcrime]

It's a paraphrase or restatement of the phrase "so long and thanks for all the fish", the title of one of the books in Douglas Adams' Hitchhiker's Guide to the Galaxy series. Changing "fish" to "bits" is interesting, as it could be "just" a reference to life in the modern age and that this individual is leaving a techie oriented job that deals with "bits and bytes". Or it could be a really on the nose "joke" making light of exactly what you say:

"GCHQ routinely hoover up personal data and spy on both their citizenry and foreign countries?"

It's hard to say which it really is.

[fundad]

doesn't bits refer to genitals?

[thombat]

In British vernacular about a quarter of all common words can be used to refer to genitals and/or intimate acts, especially when said out loud with the right intonation.

One time in London I lost my rag with a local colleague and snarled at him "is there nothing you can't make innuendo from?!?" And without missing a beat he simply leered back "in-YOUR-end-o"

[andrewflnr]

It may be more widespread in Britain, but I assure you it's equally possible anywhere. :)

[waterhouse]

On "Penn & Teller: Bullshit", there was an episode where one of the people they interviewed was a woman who's initially seen carrying a large stack of envelopes, and Penn on voiceover said something like, "We told the previous guy that we wanted to see a woman with really ... big ... envelopes. He's foreign; he didn't understand that, in America, every plural noun means tits." So there may be some regional variation.