Google has made a small but notable change, it is now showing results for punctuation mark searches. So far, punctuation marks have been ignored, just like several common words such as "of," "the" and so on.
But just like those common words are now used in the search results in some cases, punctuation marks are recognized as well.
However, the way that Google now recognizes those punctuation marks, as the Google Operating System blog
notes, is not that advanced, it just does a search for the English word corresponding to the punctuation mark.
Searches for [.], [,], [:], [;], [#], [%], [@], [^], [)], [~], [|], ["], [<], [$] all work. But not all results are relevant, for example a search for [:] is converted into a search for [colon] which retrieves results more relevant to human anatomy than to grammar.
Still, it's a start and a sign that Google is working on making more searches possible.