- Why should I care about the backing CA as long as all browsers accept it?<p>- You can register up to 100 subdomains in a certificate and up to 5 certificates per domain&#x2F;week. With their certificate expiry set at 3 months, that comes out to about 6,000 subdomains you can register. I know there are some setups where every user gets a subdomain. But I&#x27;d wager that less than 1 in 10000 LE users would run into these limits. (which may actually be lifted when the beta period ends).<p>- LE doesn&#x27;t offer any paid certificates so it&#x27;s really hard to spin this as a shareware-style incentive to spend money with them.