Also, they won't display unless you use a real live person's photo; no cartoons or drawings.
:: ostentatiously avoiding eye contact with netmeg and assorted others ::
The photograph I use on the Author page is the same one I use as an avatar on one forum-- but it happens to be a non-indexed forum, so g may not know that. It would make a difference to people who "know" me online because it confirms that I'm the same person.
Only a few days ago, prompted by a different but related question, I looked at the "pages for which YOU are the verified author" area in gwt. The identical page can show up with or without the "verified author" identification, and no clue about how they decide. Tentative guess: it depends on the exact wording of the query-- but the Verified Author won't show you the query, so this must remain tentative.
:: detour to double-check, with further detour because-- in a historical first-- a couple of the listed 404s are problems I do
want to know about, though further investigation suggests they are lying in their teeth about putative link to nonexistent pages ::
The "verified author" list has a slightly higher CTR than the same pages in the same time period overall. Probably real, not a statistical glitch-- but it's not vastly and whoppingly higher.