As others said before, it's most likely a defensive move, against other interested parties but also against Whatsapp itself. I don't use and thoroughly dislike Facebook but I'm using Whatsapp groups daily with my closest friends and my climbing mates. In that sense Whatsapp has started to move beyond SMS and towards the social network market.
With such a large user base and their established mobile presence it would have been fairly easy to challenge Facebook in the social network field, so Zuckerberg might have seen that coming as well. In that light the announcement that Whatsapp will basically stay the same actually makes sense - it will stay the same and will not develop those features that could have threatened Facebook in the long term.
Well, I already sent some messages to my friends to move on to threema, which has the added benefit of having encrypted messaging and being located in Switzerland.
With such a large user base and their established mobile presence it would have been fairly easy to challenge Facebook in the social network field, so Zuckerberg might have seen that coming as well. In that light the announcement that Whatsapp will basically stay the same actually makes sense - it will stay the same and will not develop those features that could have threatened Facebook in the long term.
Well, I already sent some messages to my friends to move on to threema, which has the added benefit of having encrypted messaging and being located in Switzerland.