When searching the mailing lists in advanced search mode we have list filtering, timeframe filtering (pretty coarse though) and then sorting mode. For moderately long running threads a search term is going to return many messages from the same thread. It would desirable to ask that only threads be shown and maybe how many individual messages in that thread matched. Going into the first message and then choosing "whole thread" (or going directly to whole thread mode) would be the typical action by the searcher who is looking to pull up a conversation they recall happened (or assumed did) and can quickly skim the whole thing for context and information.
