I think the internet gives kids the tools to get the information they need. The teacher's challenge is to get them to learn how to evaluate sources properly and not plagiarize. The internet also makes kids into published writers instantly, as anyone can create a blog.
It looks to me like the Internet has made communication a lot more interesting kids. Since it involves a fair amount of reading, I think it's generally a good thing. Let's face it, it's not like kids were doing a ton of book reading or magazine reading before the Internet developed. They were watching television and listening to music.
I would suggest that the positive impact is that more people are exposed to literacy and forced to have some level of reading ability. The more you read, the better you are at reading. The Internet has forced many different groups including teens to read more often. Of course, the level of reading improvement does depend on what you are reading. A teen who spends their time reading only social media sites isn't going to gain as much from reading the Internet as a teen that reads other media sites such as the news as well as social media. One downside to the Internet is often found when people believe anything they read there is true. I have often had students proclaim an opinion as fact or misinformation to be correct simply because they found it on the Internet. The Internet is also frequently an unreliable source in terms of grammatical accuracy. Many teens see typos, misspelling, and other errors so frequently that they have trouble recognizing these things as a mistake. Other times teens see short cuts and the type of writing acceptable in text messages so frequently they begin to think of it as normal writing. These students have trouble when they are asked to write a paper for class. They do not see the grammatical errors they are making and often include vocabulary that is unacceptable (such as lol or omg).
One positive impact of the Internet on reading and writing for teenagers is the immense amount of material available on the web for conducting research. An array of sites exist that provide valuable information on developing reading, writing, and critical thinking skills. While a trip to the local library is still a very worthwhile endeavor, the Internet does offer convenience in terms of working from home at any hour of the day.
Another positive impact is the wealth of Public Domain books available for free on the Worldwide Web. A host of classics are available at sites such as Project Gutenberg, including poetry. Project Gutenberg offers site visitors more than 40,000 free ebooks. These books, especially the work of the great writers, helps to build reading and writing skills.
A third positive impact of the Internet on reading and writing for teenagers are the online courses available for study. With some research, one can find courses at a reasonable cost that pertain to building reading and writing skills. This is especially beneficial to individuals who flourish better working alone at home, rather than in a classroom environment.
Literacy, like many educational precepts, has come to be seen in an increasingly complex light thanks to the internet. Where literacy was once simply defined as the ability to read and write, we now have new types of literacy that are not entirely related to langauge.
The visual coding of information through Windows and the internet has given rise to theories of "visual literacy" and "media literacy" which refer to a person's ability to understand and navigate information presented and represented in ways that are not entirely language-based.
These theories of new literacies suggest, to me, that one of the potential impacts of the internet is the creation of new modes of reading and writing. As a society we may be growing less capable of writing well-formed and grammatically correct sentences (perhaps), yet growing more capable of navigating increasingly robust information and entertainment systems (the internet and internet-equipped devices like tablet computers and cell-phones).
The point is this. You don't have to be literate in a traditional way to use an iPad. You do, however, need to have some sort of ability to "read" the information and interface with the machine. One kind of literacy is required.
It definitely depends on how it is used. If students use the interent, say, as a crutch, where they look things up without trying to figure them out for themselves, it can be negative. Many students will only use what they can find on the internet- such as chapter summaries or analyses of poems- without reading the actual text or trying to first understand on their own. They come to rely on the internet for everything. They also can use it to cheat on essays or other assignments.
The internet can, however, be very positive if used correctly. For writing, there are multiple websites that have tips but do not have sample essay that students can cheat off of. For reading help, if students use chapter summaries, for example, to supplement their reading and help them understand what they are reading, it is very helpful. They can use the interent for additional resources to enhance their reading of the original text, and these days research can be done on the internet alone as long as the student can trust the sources.