[DanBC]

+ might have worked perfectly, but most people didn't use it, and of those who did use it most used it incorrectly.

(http://insidesearch.blogspot.co.uk/2011/11/search-using-your...)

> we found that users typed the “+” operator in less than half a percent of all searches, and two thirds of the time, it was used incorrectly.

Check my arithmetic but that means only 1 in 600 searches used + correctly; 2 in 600 used it wrong, and the other 597 searches didn't use it at all.

[hexley]

That's what they say, but it's strange disappearance directly around the time of Google+ says otherwise.