Why is there limits?

I think its to help prevent people from using it as a chat forum, or a means to advertise (e.g. spammers). This is why you can't answer your own questions.

Also, it gives more value to the score system, and gives someone motivation to improve their score - by writing decent answers (to get best answer ratings) etc.

When you have reached your limit, you can help others by going into older Answers and RATING them.

Look for Answers on topics that you are an EXPERT. You might even use the SEARCH feature using certain Key Words. If the chosen answer looks good to you, give it a THUMBS UP. If the answer is almost right, you might just leave it alone. But if the answer is TOTALLY WRONG, then give it a THUMBS DOWN.

You will see that there are dozens of the same questions asked over and over and over again. Many of the CHOSEN answers are well explained.

Rating other people's answers is FUN. It give you a credit and gives the person that gave the good answer a point too. You see, this way, people that try hard to give good answers will get a bonus.

I would think they have limits to attempt to stop any spamming,

As without limits it would be able to go on unhindered, & that wouldn't make for a very satisfying service at all would it?

I suspect that limits are imposed to help reduce spamming and abuse of the boards.

"too much of the good thing is bad"