The Apple iPad may as well be called the Teflon Tablet for now, since challengers can't quite stick. Thanks to those 17 million iPads shipped in the second quarter, Strategy Analytics estimates that Apple held on to the 68 percent of tablet market share that IDC credited to the company in the previous season. That may not sound like a change in the status quo, but it's a significant jump from the 62 percent Apple had a year ago -- and not very good news for anyone else. Android is still holding on at 29.3 percent, although that's slightly underwhelming given the surge of extradevices in that time frame. The real hurt was dished out to Windows 7 tablets and "others" like RIM's BlackBerry PlayBook, both of whom were cut down to just 1.2 points of share each in the spring. We'll see if the newercrowd moves the needle for Android in the summer, although the well-received Nexus 7's current scarcity won't help its chances -- and both Microsoft as well as RIM are in holdingpatterns for the next several months.