The question 'Is snowboarding like wakeboarding' was one of the more common when I arrived back in Australia after my first snowboarding trip. In some ways it is, but in general not really. Sure, the principles are similar. You are standing on a board and the carving is similar, but you rarely completely stop when wakeboarding, which is where the main difference comes in. The other thing is that water tends to be very similar. Sure, it varies from salt to fresh water and what not, but snow can be totally different. You can be on rock hard icy snow one minute and on fresh powder the next.
Powder snow often means you sink a fair bit, and if you stop in soft snow it can be hard to get going again. Obviously there are a lot of differences in what you wear between the two sports as well. However, tricks are similar in many ways, as well as grinding and getting air. The only difference is that with snowboarding you are in snow, and you do not have anything pulling you along. Make no mistake though; water and snow hurt a lot if you hit them hard enough! You might think that snow is nice and fluffy, but majority of the time it hurts when you fall over!
I would suggest that for those who have done wakeboarding in the past that snowboarding is going to be easier, but it's not the end of the world. I know a few people who have never been sand boarding, wakeboarding or skate boarding that picked up snowboarding in just as little time as those who were wakeboarding every weekend.