WordPress.com and.org are two different versions of the same software. You should choose whichever you prefer as long as it is free to use. The org version requires a domain name and web server, and costs anywhere from $1 to $100 a month. The com version is a free download, but the org version requires the user to host their own website. The difference between the two versions is minor and may not be significant for your purposes.
The most recent version is 3.2. This was released on July 4, 2011. It included new multi-site functionality, a default theme named Twenty Ten, and a variety of other improvements. The post format feature has also become more popular, with 3.2 giving WordPress users a Tumblr-like experience. It includes many critical functions, such as internal linking, while the writing interface has also been simplified. Whether you use the org or com domain, the question remains: Which domain will best suit your needs?
WordPress has many advantages. Its free software makes it the most popular content management system (CMS) on the planet, with more than 38 percent of websites using it. WordPress is highly customizable, with hundreds of thousands of themes to choose from. Many of them are free. Additionally, you can hire a designer to customize the theme for your site. There is no better choice for creating a dynamic website than WordPress.