In a article mentioned in a thread some 10 weeks ago (Matt Wells interview - Gigablast search engine [webmasterworld.com]) Matt Wells said that Gigablast could hold only 320 million Web pages on the then used hard disks. It seems he invested in some new hardware. Gigablast's index is growing rapidly while existing pages are updated. As a result the index grew from 273 million on April 20 to more than 500 million now (and keeps growing at a rate of sometimes more than 10 million pages per day). Still not close to the index of Google, but very impressive and promising for a one-man search engine.
More power to the guy and it's good to see he's going from strength to strength. Even though his index isn't as big as G's I find I've been turning to Gigablast more and more lately for the quality of the search results. It's not the size that matters, more what you do with it.