By default the results of quick search are sorted by relevance. This is not always convenient, especially when using a fairly generic term. I would like to be able to sort by time.
Quick Search results are in fact boosted by their modified date. Whilst not an exact sort by date, this should mean that a result which matches your query and was modified recently will appear up the top of the results.
If you really wish to use an exact date sort, then you need to use the 'Advanced Search' option, linked from quick search in the top-right of the page.
Thanks, I am aware of that. When trying "Advanced Search" I ran into the problem that you can't group by revisions (https://answers.atlassian.com/questions/34603/the-results-of-an-advanced-search-aren-t-really-grouped-as-expected). As a first time user, it was kind of frustrating to not be able to do something as simple as "search commit comments and display matching revisions sorted by time". This comes naturally in other tools such as TortoiseSVN.