1. Materials (such as articles or videos or comments) on the internet that are trashy in nature merely for the sake of being trashy in nature. If these materials were published in more "serious" outlets of communcation, for example on television, in magazines or in books, they would never have been created or they wouldn't succeed in becoming popular. That's intertrash for you!
2. The result of writing something on the internets that you would never write or say in "real life", usually because it's exaggerated or an outright a lie. For example, playing devil's advocate in a forum, or lying about a vacation on your blog, or leaving trashy comments on a website or forum or social networking site, usually because you think it's funny.
3. The result of trolling
1. This kid is trolling. That's a lot of intertrash.
2. Did you read those comments? He's intertrashing!
3. Don't read those articles bro. Intertrash. Period.
4. Did you watch those videos? That's great intertrash!