Feedburner adds a long awaited customizable subject lines feature to email subscriptions giving emails a more professional and personalized look. Manually changing the subject lines every time to match your post was a pain. You can now use dynamic subject lines like; use ${latestItemTitle} to insert your latest post’s title into the Subject/Title of email.

All you need to do is login to your feedburner account and goto Publicize > Email Subscriptions > Email Branding and tweak the subject line.