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: â€“. 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, 'â€“', '—')
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 â€“. The key is that you also need to run the same command for the table 'node_revision':
UPDATE `node_revision` SET `title` = REPLACE(title, 'â€“', '—')
I didn't do that second step, and I drove myself up the wall trying to figure out why I was still seeing â€“ in the title field.
I hope someone benefits from this.