I have been keeping a watching brief on Mobile search and the Search Engine Journal tells us of a mashup that combines del.icio.us bookmarks with Google's mobile search tool. This allows your del.icio.us bookmarks to be mobilised, i.e. rendered for your phone browser. Whilst this is an interesting solution I have to ask why not just download Opera Mini and let it do the work, I have to say that since November when I first got a copy I have been surfing more on my phone.
I know that Web 2.0 is all about tags rather than search, but I think it will need more focus on the context under which we are look before we can say that we have found the killer app that is Mobile Search.