When a post gets old, instead of simply closing the discussion, send comments and trackbacks to the moderation queue. This will greatly reduce spam.
For documentation and tips, please refer to the official plugin page for <a href="http://planetozh.com/blog/archives/2005/02/02/wordpress-plugin-auto-moderate-comments/" title="Auto Moderate Comments" rel="nofollow ugc">Auto Moderate Comments</a>

Ozh' Auto Moderate Comments

When a post gets old, instead of simply closing the discussion, send comments and trackbacks to the moderation queue.

Make a fresh WordPress install and archive all your tweets:
<ul>
<li>It’s easier to search than on Twitter</li>
<li>WordPress is not limited to the most recent 3200 tweets</li>
<li>It will automatically expand all those ugly <code>t.co</code> links</li>
<li>All your #hashtags can be converted to WordPress tags</li>
</ul>
Plugin’s page: <a href="http://planetozh.com/blog/my-projects/ozh-tweet-archiver-backup-twitter-with-wordpress/" title="Ozh' Tweet Archiver" rel="nofollow ugc">Ozh’ Tweet Archiver</a>
Live example: <a href="http://planetozh.com/tweets/" title="Ozh' Tweets" rel="nofollow ugc">Ozh’ Tweets</a>
Development: <a href="https://github.com/ozh/ozh-tweet-archiver" rel="nofollow ugc">on Github</a>

Ozh' Tweet Archiver

Import and archive your tweets with WordPress

Ozh' Auto Moderate Comments vs Ozh' Tweet Archiver