The advent of the tablet has changed the way we do many things. Tablets allow us to surf the web, play games, check email, and consume media in ways – and places – that were once much more complicated. One of the more recent and unexpected use of tablets, though, has been as a second screen when we’re watching our TVs.

According to a recent report from Forrester, 85% of tablet owners use their devices while watching TV. What’s more, 30% of all tablet use is done while watching TV. Tablets allow users to enhance their TV watching experience in a variety of ways. Apps like GetGlue let you share what you’re watching with friends, while Miso shows you content related to what you’re watching on your TV. Even apps like IMDB and Wikipedia can come into play: how often have you seen an actor on the screen and wondered what else they’ve played in?

The report also found that 18% of tablet owners take advantage of their devices’ ability to connect to their living room TV via HDMI or VGA cable, a feature that is available on the iPad 2 and new iPad, as well as on several models of Android tablet. In fact, these users are more likely to turn to their tablet than the built-in features of their “Smart TV” for certain kinds of content.

Interestingly, the study also found that tablets are taking a bite out of the market for smallers (24 inches or less) TVs. Nearly a third – 32% – of tablet owners said they would not be buying such a TV in the future. These same tablet owners, however, said that they watched more video than before they bought their tablets. They also said that they used their tablets to watch video in the kinds of places they had never been able to do so before, including the kitchen, the bathroom, airports, and more.

When Tim Cook introduced the new iPad last month, he talked a lot about the iPad’s role in what he called the “post-PC era,” for which the iPad was the “poster child.” While it would certainly not be accurate to talk about the iPad’s role in a post-TV era (a 10-inch screen will never beat a 40-inch screen, no matter how many pixels you cram in), this report suggests that the rise of the tablet has had a major impact on how we watch TV.

What do you think? Do you have your tablet with you when you watch TV? What about your smartphone? What do you think of the second screen experience? Do you use your tablet to watch TV in places you couldn’t before? Tell us about it in the comments.