No matter where you post your ad on craiglist it's going to receive some traffic. Of course some sections or categories receive more traffic than others but no matter what your ad will be viewed. The real trick is placing your ad in the right category or section to target your customer.
Usually it's pretty easy to choose the best category for your product or service because you already know a lot about it. The real question you have to consider is... are you placing your ad in a category best suited to attract your potential customers? Placing your ad in the correct category can be the different between 50 visitors and 500 visitors.
Make sure that when you post on craigslist you spend the time to make sure that you're doing it in a way that will target your customers properly. For example, if you're offering home loans you can do it in the services section where it probably should be or you could do it in the homes for sale section. This is a choice that is ultimately up to you and you need to test your results.
Most of the time when you post in the wrong category craigslist views get upset and tend to flag your ad as miscategorized. If your ad is flagged down quickly you've basically wasted your time posting and probably shouldn't even bother doing it at all. Create ads that will stick and if you're getting flagged down it should be a hint you're doing something wrong.
There is a lot of possibilties with marketing on craigslist and being smart about reaching your customers is always important. For example you could respond to agents in the homes for sale section on craigslist and ask them if they'd like to partner with you. They are essentially part of a the same market but they don't directly compete with you.
Every visitor that responds to their ad would also receive message from them about your home loan services. This is a great method to target potential customers while building successful and profitable relationships. Oh and did I mention that they are posting ads for you as well?