Jane,
If you attach your MacBook via a Mini-Display-Port-to-HDMI adapter and a HDMI cable to an HDMI input of a Samsung SmartTV, the TV effectively acts as an external display to your MacBook (make sure you switch the input of the TV to the HDMI port you plugged aforementioned HDMI cable into) and as such there ought not be any limitations to what content you can display on it - anything that can play back, stream, or display on your MacBook's built-in display can also do so on this TV.
To configure what your MacBook displays on the attached TV, load your Displays panel in your System Preferences (in your Apple menu at the upper left hand corner of your screen). If it doesn't look like your TV is receiving a signal from your MacBook even though you've verified that your TV's input has been switched to the HDMI input you plugged the connected cable into, check your physical connections and/or click the "Detect Displays" button in the Displays panel.
Once it looks like your TV is receiving video from your MacBook, take a look at the "Arrangement" tab that should be visible in the Displays panel whenever there is an active connection to an external display. In the Arrangement tab you can switch mirroring (showing the same content on the MacBook's built-in display and the external display) on and off with a checkbox at the bottom of the panel.
Mirroring is the least complicated way to configure your display connection to your TV, but it's got the potential disadvantage of not utilizing the full display resolution of your TV, since when you mirror your MacBook's built-in display, what's showing on the TV screen will essentially be a scaled up version of what you see on your MacBook.
Then again, if you're watching online streaming content that likely wouldn't take advantage of your TV's full 1920x1080 HD resolution anyway, this might not matter and you might be happier with a mirrored MacBook display than figuring out how to arrange two desktops and move browser windows from your MacBook across to the un-mirrored TV display. Though, honestly, that isn't so hard to figure out - once you've turned off mirroring just play with the little representations of your built-in display (the smaller rectangle with the white bar across the top representing your menu) and your TV (the larger rectangle without a white bar across the top) in the Arrangement tab that will control their relative spatial arrangement to one another.
Say—in an unmirrored display arrangement—you dragged the larger rectangle representing the TV to sit center atop the smaller rectangle representing your MacBook's screen - with this display arrangement you would move your mouse pointer from the latter to the former by moving it up beyond the menu bar at the top and it'll immediately appear at the bottom edge of the TV (and vice versa - the TV display virtually attaches the to top of the built-in display). In this arrangement you could grab a web browser window and drag it up past the menu bar to appear on the TV screen. Once you dragged a window to the TV screen you ought to be able to switch whatever it is you're playing back to full screen mode and see a seamless image on your TV.
Once you got the display of content going to the TV configured to your liking, consider clicking on "Show All" on top of the System Preferences window to back out of the Displays panel and open the Sound panel to switch your MacBook's sound output from its built-in speakers to your TV's speakers, which ought to be appear in the list of sound output options with an active HDMI connection to a device capable of sound output (given that HDMI is capable of transferring audio as well).
All that said - if you bought a brand-new Smart TV, why not do all the streaming you wish to do directly on the TV? A Smart TV is essentially a TV with an integrated set top box, meaning you can use applications installed on the TV directly to stream Netflix and a large host of other streaming providers without the need to tie up your laptop for the purpose. Here is a link to Samsung's overview of their 2013 Smart TV feature set.
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