In an era of burner accounts, keeping a long-standing handle shows a person who stands by their digital footprint.
Most likely, we’re looking at someone born in 1983. This puts them right in the sweet spot of the "Xennial" generation—people who remember a world before the internet but were young enough to master it as it arrived.
Many people with these types of handles are the backbone of niche communities—the ones providing the helpful tech tip or the deep-cut movie recommendation.
While the internet is home to many "Jacks," the specific combination of kjack83 suggests a few things: