I'm posting this to save others some time.

When I migrated content from another CMS to Drupal 7, the em-dash (—) in the title field of many nodes turned into this: –. If this happens to you, you'll need to execute the following command from php-myadmin or the command line:

UPDATE `node` SET `title` = REPLACE(title, '–', '—')

But that won't solve the problem entirely. You might see the em-dash when you search for content, but when you go to the page, it will be replaced by –. The key is that you also need to run the same command for the table 'node_revision':

UPDATE `node_revision` SET `title` = REPLACE(title, '–', '—')

I didn't do that second step, and I drove myself up the wall trying to figure out why I was still seeing – in the title field.

I hope someone benefits from this.