Saw a very good idea posted in a 23andMe community thread today (log-in required) – Relative Finder should show the estimated birth year of the common ancestor shared by yourself and each match.
Well, now it does! Be aware that the calculation is based on your year of birth, so please make sure this is set correctly in your profile.
As always, if you already have the extension you’ll get the update automatically. If not, head to the download page.