WordPress is a wonderful advertising tool. Everything you post gets priority on search engines. You can organize everything into categories, and you can create a link back to your website.
You can easily transfer ownership of the blogs to another person, without losing any data.
They are great advertisement tools. However, if you are trying to make money with your information, stay away from WordPress.
Let us say you are a handyman and want to share your skills with the world. Anything you post on WordPress is free for anyone to use. You do not own the information, you do not own the WordPress site, you cannot add ads to the site and make money.
In short, a WordPress blog is not fully yours. It is a great advertising tool, but do not post information you hope to get paid for someday.
YouTube is fun and easy, and a great pay to get your face on the front of Google searches. Once you post a video, there are hundreds of websites waiting to take your video and post it on their websites to increase their SEO.
These websites take traffic meant for your site, but they also provide advertising for your material. I find them annoying, but you must realize they are out there. Always put your url in the title of the video, so people can find their way to your website if they like your material.
Twitter is probably my least favorite for small business.
Twitter is great for celebrities, or maybe a close circle of friends. I have yet to find any true value in it for small business.
If you wanted to announce a sale, there is generally not enough room to announce the sale, and the terms and conditions. For example, sales usually only last for a set period of time. You generally do not have enough room to state this in a tweet. If you have a lot of short messages on value to consumers, Twitter may be right for you. Otherwise, you may want to stay away.