I've noticed more and more sites displaying full page ads over the content which only disappear after the advertisement is finished playing. Safari 5 provides a quick way to get to textual content without viewing the ad.
Simply enter Safari's 'Reader' mode to see the main content of the page instantly. For other browsers, Arc90 Lab's bookmarklet Readability does the trick as well.
[crarko adds: You won't always be able to switch to Reader mode in Safari 5; it's dependent on the markup used on the site in question. Readability is the more flexible solution, and ClickToFlash may be helpful as well in some cases. Of course ad creators are aware of these tools, and come up with creative ways to foil them. Hopefully that same creative thought can be used to make the ads themselves more interesting. That does seem to be one of the goals of iAd. I wonder how big a dent Apple will ultimately make in that industry.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20101202112305610