Save your user activity from Metafilter to a SQLite database.
Clone this repository, then run python setup.py install.
If you are logged in, then you can download a file containing your comments here. Note that you are only able to do this once per week.
You can then process this file using the command:
$ metafilter-to-sqlite comments -f /path/to/my-mefi-comments.txt metafilter.db
You can scrape posts from a MetaFilter user profile using the command:
$ metafilter-to-sqlite posts metafilter.db <user_id>
where <user_id> is the numerical id (not username) of an account.
This can only import comments and posts that you have made; it does not save comments or posts by other users that you have favourited.
This information could be obtained by web-scraping in the future.