Icons - The 5 second rule
Icons are a useful navigational cue, and a hugely distracting design side-alley in which you can get (enjoyably) lost forever, but how effective are they at enhancing user experience? My approach is that, like colour coding, if you have too many variables it takes too long for the user to decode them - and if they aren't recognisable pretty much straight away they serve no purpose.
So it's good to see that reinforced here: https://www.nngroup.com/articles/icon-usability/ amongst a number of other useful observations.
If it takes you more than 5 seconds to think of an appropriate icon for something, it is unlikely that an icon can effectively communicate that meaning.
One thing that still puzzles me is that if, as the article observes, it's best to have labels with icons - then why have the icons at all? Two obvious reasons: it makes the link easier to click, and it enhances the style of the site and reinforces the brand by virtue of the styling (but that in itself isn't a good enough reason).
If it works well, then the icon generates the meaning by itself and the text is just a 'backup'. If the icon is universal (the search spyglass or the email envelope for example) then so much the better, and if it is a well designed, distinctive and memorable visual it also picks up currency with regular users over time. If we can assume that pictorial content is more quickly processed than textual then maybe icons are as valuable as we believe.
There's probably an entire blog we could dedicate to this, and if we wanted to show off we'd reference anthropology, Egyptology and semiology, (http://bit.ly/2nKuisr) , but I guess, like every other aspect of what we do, we just need a working solution rather than an ology: Yes we like icons, but they'd better be good :)