NP, you'll notice that the number of hours you are able to record goes down a lot (with my nearly full SD card it goes down to just under 7 hours from over 43 hours in the "high" (VGA) setting. So you'll want to make sure you move the videos to your computer if you plan to take a lot of them. The videos will be large.
What do you mean share them? HD videos are large files. You can't "share" them regardless of the platform because most email providers won't allow files that large. You can save them to your computer and you should should be able to upload them to youtube and share them that way.