The Dell Streak (shoutout to the other 3 people who bought one) had a 5 inch screen in 2010, a notable jump from contemporary phones like the iPhone 4 which was still 3.5", and other Android devices like the HTC Droid series which were around 3.7" and slowly starting to creep upwards to differentiate themselves from the iPhone. I think the largest Android devices you could get at the time were still smaller than 4".