I use twitter and wanted a solution to back up my tweets. A 3rd party service If This, Then That lets you set up "triggers" which can monitor for your tweets and other people's tweets that mention you, and then email them to you. You could then archive the emails. I use a small python script to filter the mails for archiving.

IFTTT used to support tweets and mentions natively, but sadly they stopped due to a braindead twitter API change. It is still possible to use IFTTT for this purpose, but you have to construct a URL to an RSS feed in the twitter API. Here are the URLs for my tweets and my mentions. Just swap your username in:

Here's the python script I used to tidy up the emails. The resulting mails look like

From: username <>
Date: whenever
Subject: tweet text

You will have to configure your mail setup to recognise the IFTTT mails and filter them accordingly. One way is to use a unique address for IFTTT and assume all mail from it will be tweets. Other ways would be to add a custom secret subject prefix and adjust the python script accordingly; or add a unique secret word in the body of the message.

Here's an example procmail recipe that assumes you've used a secret, unique email address for this one purpose: