WordPress currently supports importing data in the form of posts (articles) and most of the details or features supported by the content publishing platform.
Many of the following Content Import scripts can be found under Tools → Import menu of your WordPress Administration Screens.
If you run into specific problems, a search on the WordPress Support Forum will likely lead to a solution, or try the Codex FAQ. Users of a blogging system not listed here who wish to switch to WordPress are invited to ask for help in the WordPress Support Forum as well.
To help you understand the differences between WordPress and other existing software, we recommend you review the WordPress Features and more on Working with WordPress.
If your exported file is very large, the import script may run into your host’s configured memory limit for PHP.
A message like «Fatal error: Allowed memory size of 8388608 bytes exhausted» indicates that the script can’t successfully import your XML file under the current PHP memory limit. If you have access to the php.ini file, you can manually increase the limit; if you do not (your WordPress installation is hosted on a shared server, for instance), you will have to break your exported XML file into several smaller pieces and run the import script one at a time.
If the import process is run again with the same data file after stopping midway through, it could result in duplicate data, missing data or other errors in the destination database.
For those with shared hosting, the best alternative may be to consult hosting support to determine the safest approach for running the import. A host may be willing to temporarily lift the memory limit and/or run the process directly from their end.