I recently came to know that wordpress.com and wordpress.org are two different platforms for publishing. But despite browsing on various links I am not able to fully understand the actual difference between both in terms of blogging. I am a hobbyist blogger and my requirement is just to increase outreach and readability and not in customizing the publishing themes etc. Since I write only as hobby, I'd like to use free one - so I have currently picked up wordpress.com since it takes care everything without paying.
WordPress is software, which can be self-hosted (run on your own computers/dedicated servers).
The .org website lets you download the software and run it for yourself. This route is for the more technically literate, who know what they're doing.
On the other hand, the .com version is where the company hosts blogs for other people instead (at some costs).
One is where you can connect to the millions of sites already created -- .com. The other -- .org -- is where you sign up to create your own site. The two are fundamentally different. If you want to be a blogger, you want the second one. I have done this and created a blog very easily.
Is the "more commercial" product of them. The product that is easy to get, configure and launch. They take care of the setup of wordpress site, and you have somehow limited control. They also win from a few adds places on your website and so on. You have control over the activated theme, plugins and so on, but limited control over the platform/hosting itself.
On the other hand,
Is the full control version of the platform. If you have a few developer skills, you can download the platform for free, and then buy a domain, a hosting plan, and install the platform there. You can create your own theme from scratch, or use one of the predefined themes that comes with the platform package download.
If you want full control over the platform, buy your own domain, hosting, and head over wordpress.org for a free copy of the platform.
If you don't have developer skills and you want an easy to maintain setup, choose wordpress.com
There is an in-between. Many ISPs have Wordpress as part of the package you purchase from them.
I use a great local company who offers both internet access and online accounts separately. The accounts give you domain name services (they'll take care of registration and bill you the $15 or so annual fee), full email services and mailboxes, mailing lists, and a full implementation of Wordpress where you don't need to have root access to a server or host your own in any way. It's worth the $10/month to me. (You can find these things cheaper but I'd rather pay more for a company I trust.)
This is a Wordpress.org solution where you don't have to do the tech end. Just pick a theme, fill out a couple lines, and start writing (if you want to do more complex setups, you can).
Consider the restrictions of Wordpress.com and of other hosted sites. Mine has no restrictions aside from extremes of content, spam, etc. I can have paid advertising, run a commercial site, or have adult-only content. I can upload any plugins or themes that I wish. On Wordpress.com, you're not allowed to run ads or use plugins/themes beyond what they have themselves.
WordPress.com is very strict in protecting their services from abuse. They suspend blogs suspected of activities prohibited in their terms of service. Visitors can also report a blog. WordPress.com allows suspended blogs to export their posts for a limited time. Also WordPress.com may not even notify or ask a blog owner to remove content. This means that usually there is no warning for the blog owner. Once a blog is suspended the WordPress.com subdomain will be held and will not be released for anyone else to use. (ref)
This is great if the "abuse" is illegal activity, but we don't actually know where their lines are. Facebook would take down photos showing children breastfeeding because they violated their nudity rules. Yahoogroups removes accounts with no warning to the owner if they get too many complaints (I was active on a list this happened to and I can say there was nothing wrong going on).
Obviously you have to choose your hosting site with care, but the good ones will have human beings read the complaints and decide what to do. If they are legitimate, they'll talk with the site owner and work out a plan. They don't just use algorithms (or traumatized workers) to yank your account out from under you.
You can always start with a free site and see where it takes you. But have backups.