When you start a blog at WordPress.com, you’ll discover something wonderful, should you dig deep enough into the system settings: You can take it with you if you decide to leave. WordPress offers a backup system that includes a way to email the entire database of content to yourself at regular intervals, and the open-source WordPress community has written many plug-ins to make this and similar processes easy and robust.
Even when you can readily get your data out of a site or service, that doesn’t mean you’re home free. Downloading the WordPress database is only the first step if you want to move it into another blogging software system. It can be done, but it’s not always easy.
The WordPress community is serious about this issue, though, and it’s offering support to a movement that is gaining strength in this era of multiple sites and services where we post words, pictures, videos and more. The movement wants to make our data portable, so that we aren’t locked into someone else’s system or method of doing things.
In general, when you’re using other people’s services you should always look for evidence that you can get out what you’ve put in. You should also keep copies of pictures and videos you upload.