It has become trendy to tack poems, photos, icons, logos and other digital flotsam and jetsam onto e-mail messages. We understand that digital signatures have a practical use, particularly when they provide the kind of info you'd see on a business card. And we don't doubt that, for some people, a U2 lyric can express how they feel better than they could. But the 3-D animations and other digital doodads created with the help of Meez and other sites of its ilk Blingee, Iconator are just plain annoying. They also clog the recipient's inbox with unnecessary bits. Sites like Smiley Central, which offers a seemingly endless assortment of cutesy creatures for dressing up e-mail, instant messages and blog posts, require you to download a browser plug-in. The company insists the app is neither spyware nor adware, but it can still slow your computer down.