The Heartbleed bug created a massive security hole and left websites scrambling to find a fix, but a new HuffPost/YouGov poll shows few Americans have heard much about it, much less done anything to make sure their own online presence is secure. Only 23 percent of respondents have even checked to see if any websites they use were affected by the bug, while 77 percent said they have not checked. Slightly more people — 38 percent — have changed their passwords, including 6 percent who have changed all of them, 16 percent who have changed some of them, and 16