Not only will you have some people that will take advantage of this and take articles and you'll never hear from them again, but it simply isn't a good use of your time.
Potential clients want to know that you can string together a least six words in a coherent sentence. They want to see how your writing flows. They want to see if you're capable of writing at the caliber they desire.
Two options are better:
1. Have a website for your writing and have samples on it.
2. Have a niche site that may not necessarily be for writing clients, but it does show good examples of how you write and what your style is.
The best part about directing your clients to a niche site, is that you can constantly be updating the content on there - so you are building your own business while you're working for clients as well.
This also helps you get around the problem of not having referrals if you are a ghostwriter (because many clients don't want others to know that your writing for them).
Just a little piece of advice from someone who got her first writing gig from showing the client a few hobby blogs as proof of her writing skills.
Any other writers want to give some advice about getting your FIRST client?