Next time you're feeling nostalgic and want to peruse old Twitter posts -- such as in 2006, when Pluto was demoted to dwarf planet status -- you might want to pay Topsy a visit. The social search engine, which could previously look for posts up until 2010, has expanded its archives to include tweets from as far back as Twitter's birth in 2006. Simply input terms in the search box, and you'll find their newest and ol
