I'm not a financial expert, so I don't know all the pros and cons, but I feel that there are two conflicting desires which you are trying to balance.
1: You want Newgrounds to be successful (not that it already isn't!) and grow as much as possible.
2: You don't want to lose Newgrounds.
You built all this by yourself, so I can only imagine what you could do with one metric fuck-ton of money. On the other hand Newgrounds is Newgrounds because of you Tom, and I don't like to think what would happen if it got taken away due to lack of profits.
As I really like Newgrounds the way it is right now, the risk doesn't seem worth it. BUT, I have faith that you could do something amazing if given the opportunity. As you have all the necessary information at your disposal to make the best decision, I think you should think long and hard about this, maybe consult some professionals, and do whatever you think is the best. Either way you'll have the support of one of the most rabid fanbases on the internet.
Thanks for letting us weigh in on this!