Third-person singular simple present indicative form of sign off.
Signs-off Sentence Examples
On his blog, he often signs off with the phrase and says it at least once or twice during interviews.
And, once your little one signs off the site, the noise, chaos, and mess of those mischievous young ones she's been caring for will disappear into the cyberspace void--certainly a tad more convenient than the real thing.
Kristen Bell (of Veronica Mars and Heroes) voices the erstwhile title character and signs off her erstwhile narrations with xoxo, Gossip Girl.