Everyone knows about Google +, Google's social network, but the old Google + was the use of the + sign in the Google search box for exact matching on your keyword searches.
Google described this operator on their Google search operator help page as:
Search exactly as is (+)
Google employs synonyms automatically, so that it finds pages that mention, for example, childcare for the query [ child care ] (with a space), or California history for the query [ ca history ]. But sometimes Google helps out a little too much and gives you a synonym when you don't really want it. By attaching a + immediately before a word (remember, don't add a space after the +), you are telling Google to match that word precisely as you typed it. Putting double quotes around a single word will do the same thing.
Google recently removed this from the page and no longer supports this special operator.
There are some complaints in the Google Web Search Help forums, in which Kelly F. from Google replied that you can still get the same results with the quote operator. She explained:
We've made the ways you can tell Google exactly what you want more consistent by expanding the functionality of the quotation marks operator. In addition to using this operator to search for an exact phrase, you can now add quotation marks around a single word to tell Google to match that word precisely. So, if in the past you would have searched for [magazine +latina], you should now search for [magazine "latina"].
Are you sad to see one of Google's oldest search operators go away? Do you suspect it has to do with confusion around Google +, the social network?
Forum discussion at Google Web Search Help.