I’ve written about donation programs that turn our older model mobile phones into money to assist battered women and other people in need of help and counseling. Frankly, disposing of outdated phones is tough to do. It’s not because we don’t want to; it’s because we haven’t had a really good reason to dig into those drawers. (I’ll bet many of us could go into a drawer and pull out a couple of mobile phones. At my house we count four unused feature phones (maybe more) in mothballs right now.) Online marketplaces (example, eBay) and brick-and-mortar chains including Best Buy have introduced programs that offer us cash or store credit for our old model mobile phones. What’s the deal? Best Buy’s buy-back plan is all about keeping you as a customer. Meantime, eBay’s promotion comes without strings attached. In fact, eBay Instant Sale (effective through February 22) offers consumers cash guarantees of $200 for select functional smartphone models and up to $450 for AT&T iPhone 4s. According to a press release, eBay users can take a $200 guaranteed price on any functional iPhone 3GS, Motorola Droid X, HTC Evo 4G and Samsung Galaxy S Vibrant smartphone models. Customers can also receive a minimum of $200 and up to $450 for the AT&T iPhone 4 during the eBay Instant Sale promotion. Nielsen believes that we’ll see 50 percent smartphone penetration in the U.S. by the end of 2011. But that shift will require consumers to trade up from their feature phones, a mobile makeover that will likely only come about if mobile operators offer free (subsidized) smartphones with contracts, or we see more schemes (such as the one from eBay) allow consumers to trade up or sell the devices they don’t want. As marketers, we should continue to plan mass smartphone adoption into our strategies. But we should also remember that – despite the wave of buy-back offers — there will still be more than 150,000 feature phones in circulation by the end of 2011. More in my column here http://bit.ly/eRARmv.