You automatically own a copyright on any intellectual property (any original writings, poetry, music, lyrics, etc.) that you create. So, no, it is not illegal to 'slap a copyright sign' at the bottom of your webpage. Also, any graphics or photographs you specifically create, you own the copyright to as well. Which is why you need a release to copy a photo on those machines at Wal*Mart, K-Mart, etc. The Photographer, not the subject, owns the copyright from the instant that the work is created.However, if you come up with some genuious literary work and you want to publish it, you may want to register the copyright with the Govt. as soon as possible. Regestering a copyright for your intellectual works ASAP will give you more than enough to sue someone for Copyright Infringement.So go ahead and slap that symbol on anything original that you create.I'm not as well versed on a Trade Mark, I do believe that to have a trademark, you need to register that with the proper agencies. Also, this doesn't apply to most physical things outside of photographs, artwork, and the like. If you invent some wonderful new gadget, you need to apply for a Patent (again, ASAP) to prove that you invented it.P.S., also for any original writings or photographs that you create, you may want to look into licensing them as well. This can be done for free thru a Creative Commons License (obviously just Google that), and they offer different Licenses. When you License something, that is giving someone permission on how to use your original copyrighted/licensed material (or it is Not giving someone any permissions, or only restricted permissions, etc. Creative Commons can go in to more detail).ALWAYS PROTECT YOUR ORIGINAL WORKS .