Usually, I browse while programming.
That is, at times, I go through some reddit links, some slashdot article, and do my job in between; some other times, I do my job and browse in between (and of course, sometimes I only do one, or the other).
I used to feel guilty about it and then I realized: most people in the company do the same. Most people in my previous company did the same (and I think they still do).
Most people in the company before that, didn't. At all! Working in that place was never fun (of course not, it was supposed to be professional, not fun; Thus, you usually ended up chatting with a colleague, bothering (or not) somebody else, which was unprofessional also (and interrupted two persons instead of one).
I think being serious all the time sounds nice, but only in theory, and only to serious people.
This seriousness at my last employment place was imposed by management; it was a we're busy and have no time to loose on company time or we have a deadline to reach or simply well ... you're payed for eight hours of work!
In my view though, it was simply we take ourselves too seriously around here, so stop trying to have fun, while working.
I realize that, taken to extreme, if nobody does anything, you - as a company - have nothing to sell. My argument though, is not about the extreme cases, except to say that in both extremes, somebody looses (all work and no play makes nine hours of your day extremely dull and all play and no work makes your employment kind-of short, as the company will have no money to give you).
The seriousness at my last employment place was also one of the main reasons I left (well ... that and the BS I got when I asked for a salary raise).
Still, this half-half division is something I feel is beneficial to both the company and myself. I will probably not try to justify this to the CEO anytime soon, but I still think that.
Also, all this theory aside, when we have an emergency I leave the auxiliary activities down and focus on the emergency.