At their inception in late 2007 as smaller notebooks optimized for low weight and low cost—netbooks omitted certain features (e.g., the optical drive), featured smaller screens and keyboards, and offered reduced computing power when compared to a full-sized laptop. Over the course of their evolution, netbooks have ranged in size from below 5" screen diagonal to 12". A typical weight is 1 kg (2.2 pounds). Often significantly less expensive than other laptops, by mid-2009, netbooks began to be offered by some wireless data carriers to their users "free of charge", with an extended service contract purchase.
In the short period since their appearance, netbooks grew in size and features, and converged with smaller, lighter laptops and subnotebooks. By August 2009, when comparing a Dell netbook to a Dell notebook, CNET called netbooks "nothing more than smaller, cheaper notebooks", noting, "the specs are so similar that the average shopper would likely be confused as to why one is better than the other", and "the only conclusion is that there really is no distinction between the devices". In an attempt to prevent cannibalizing the more lucrative laptops in their lineup, manufacturers imposed several constraints on netbooks; however this would soon push netbooks into a niche where they had few distinctive advantages over traditional laptops or tablet computers (see below).
By 2011, the increasing popularity of tablet computers (particularly the iPad )—a different form factor, but with improved computing capabilities and lower production cost—had led to a decline in netbook sales.