Breaking links and feeds
I just spent a bit reviewing a list of the feeds that hadn’t had any new posts for a while and finding a bunch that had moved. Instead of serving up a nice HTTP 301 with the new feed they instead had a post saying “Here’s my new blog, come check it out!”. That makes me crazy. It makes me even more crazy when the “new” blog is also out of date. Of course, very few blogging tools make it easy to serve a redirect in place of the feed. Technical people still have no excuse.
It also makes me crazy when people just break all their old post references instead of serving a redirect to the new site.
It’s so much nicer when someone moving to a new site makes the effort to ensure no feed readers watching the old site get broken and nobody coming across links into the old site get disappointed by a 404.