Marking up Web pages is nothing new. Offerings like Sharedcopy, MyStickies and Stickis allow you to annotate any Web page and, in some cases, share those annotations with others. However, a new entry into this genre, Blerp, adds a new twist to the practice. Blerp, currently in its alpha phase, is the brainchild of the folks at RocketOn. The company’s eponymously named first product allows anyone to create a virtual world that will run on any Web site. Like other markup programs, Blerp lets you post comments to any Web page.