Positive indicators:

• Passionate about technology
• Programs as a hobby
• Will talk your ear off on a technical subject if encouraged
• Significant (and often numerous) personal side-projects over the years
• Learns new technologies on his/her own
• Opinionated about which technologies are better for various usages
• Very uncomfortable about the idea of working with a technology he doesn’t believe to be “right”
• Clearly smart, can have great conversations on a variety of topics
• Started programming long before university/work
• Has some hidden “icebergs”, large personal projects under the CV radar
• Knowledge of a large variety of unrelated technologies (may not be on CV)

Negative indicators:

• Programming is a day job
• Don’t really want to “talk shop”, even when encouraged to
• Learns new technologies in company-sponsored courses
• Happy to work with whatever technology you’ve picked, “all technologies are good”
• Doesn’t seem too smart
• Started programming at university
• All programming experience is on the CV
• Focused mainly on one or two technology stacks (e.g. everything to do with developing a java application), with no experience outside of it