[ReverseCold]

Expired certificate is probably the least egregious security error, especially for a homepage.

No data is lost or stolen. Customers won't like it, you may lose sales, etc, but your data security is fine.

[theli0nheart]

It's a sign of either laziness, incompetence, or lost interest, and none of those things are good.

[ReverseCold]

Not to say that an expired cert isn't bad of course :)