Security concerns for twitter widget

I would like to embed the twitter website widget to get a live stream of twitter updates on the site.  Would also like to embed youtube or ted videos.  Are there legitimate security concerns to keep in mind when I do this?

Embed videos into sites
http://www.ted.com/talks/steven_cowley_fusion_is_energy_s_future.html 
<!--copy and paste-->
<object width="446" height="326">
 <param name="movie" value="http://video.ted.com/assets/player/swf/EmbedPlayer.swf"></param>
 <param name="allowFullScreen" value="true" /><param name="wmode" value="transparent"></param>
 <param name="bgColor" value="#ffffff"></param> 
 <param name="flashvars" value="vu=http://video.ted.com/talks/dynamic/StevenCowley_2009G-medium.flv&su=http://images.ted.com/images/ted/tedindex/embed-posters/StevenCowley-2009G.embed_thumbnail.jpg&vw=432&vh=240&ap=0&ti=718&introDuration=16500&adDuration=4000&postAdDuration=2000&adKeys=talk=steven_cowley_fusion_is_energy_s_future;year=2009;theme=speaking_at_tedglobal2009;theme=bold_predictions_stern_warnings;theme=new_on_ted_com;theme=a_greener_future;theme=unconventional_explanations;event=TEDGlobal+2009;&preAdTag=tconf.ted/embed;tile=1;sz=512x288;" />
<embed src="http://video.ted.com/assets/player/swf/EmbedPlayer.swf" pluginspace="http://www.macromedia.com/go/getflashplayer" type="application/x-shockwave-flash" wmode="transparent" bgColor="#ffffff" width="446" height="326" allowFullScreen="true" flashvars="vu=http://video.ted.com/talks/dynamic/StevenCowley_2009G-medium.flv&su=http://images.ted.com/images/ted/tedindex/embed-posters/StevenCowley-2009G.embed_thumbnail.jpg&vw=432&vh=240&ap=0&ti=718&introDuration=16500&adDuration=4000&postAdDuration=2000&adKeys=talk=steven_cowley_fusion_is_energy_s_future;year=2009;theme=speaking_at_tedglobal2009;theme=bold_predictions_stern_warnings;theme=new_on_ted_com;theme=a_greener_future;theme=unconventional_explanations;event=TEDGlobal+2009;"></embed>
</object>

Twitter Feed
http://help.twitter.com/forums/10711/entries/15354 
<script src="http://widgets.twimg.com/j/2/widget.js"></script>
<script>
new TWTR.Widget({
  version: 2,
  type: 'profile',
  rpp: 4,
  interval: 6000,
  width: 250,
  height: 300,
  theme: {
    shell: {
      background: '#333333',
      color: '#ffffff'
    },
    tweets: {
      background: '#000000',
      color: '#ffffff',
      links: '#4aed05'
    }
  },
  features: {
    scrollbar: false,
    loop: false,
    live: false,
    hashtags: true,
    timestamp: true,
    avatars: false,
    behavior: 'all'
  }
}).render().setUser('sapnetwork').start();
</script>

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