Twitter turned of their searh features during the heaviest traffic storm since the US election. "The problems were so great, that Twitter had to disable some features like search, arguably the site's most resource-hungry one." - Kasper Sorensen from Bookmarklet

Also keep in mind that Twitter Search routinely reaches back only 7-14 days anymore, even when it's working. It's a big problem when you want to look at older stuff you or someone else posted. In effect you need to do your own archiving, else you don't even have minimal search capabilities over those tweets. - Alex Schleber