Bitcoin is permission-less, so by it's design anyone can copy and hardfork it. Anyone can make a "bitcoin dog" or whatever anytime. The question is whether you can rally a community around your hardfork so the coin actually has value, this is much harder to do. I imagine in the future crappy hardforks will be harder and harder to pull off as people start to see they have no real value. Right now there is a tendency for people to see it has free money which gives the new coin some value.
Yup, there have been hundres of forks. anyone can do it. Most have near-zero value.
i just found a very interesting website (
http://mapofcoins.com/) which has interesting information about forks from different cryptocurrencies.
the bitcoin fork map (
http://mapofcoins.com/bitcoin) specially took my attention.
according to this site there has been
667 forks in total, 3 of which belong to this month alone.
you can click on the names of these coins and see the code and their website. a lot of them didn't even bother making more than 20 commits in years! or even change anything meaningful when they fork!