is there a limit for mylot posting?

You can post as much as you want without limits, provided that you are posting quality comments and discussions according to the MyLot guidelines. If you are posting spam, polling questions, or are answering discussions with less than a complete sentence, you will find that MyLot will eventually delete those discussions (it may take them some time) and take away credits and earnings. It's best to follow the guidelines and put a little bit of effort into this; that's your best chance at being successful and maximizing your earnings.

i don't think that there is a limit for mylot postings.but there is a limit for the no of postings you can make.i personally can't spend the whole of my day infront of the computer and so i can only post a limited amount of postings a day.but i have seen people who have done it.they have made good money out of it too.

There is no limit to the number of posts you can make. I ever see people making a few hundred posts a day. And you do get paid for the efforts you have make. If time is what you have, you can really do a lot.