For example if I use google.info to create my website will I be sue. Or if I use the word YouTube and create a website name youtubeforum.com will I be sue?? Thanks
I think you will be sued when using "google" in any domain. They can even sue you if you use their logo image on the net.
Its not as simple as "no", you will see many 1 word generic domains are owned by different people (eg Insure.com -v- Insure.co.uk) and despite some of those having very deep pockets for lawyers the others are still in existence. It will depend on what the domain is, if its a trademark or not, if its a dictionary word or nor, what you and they are doing with the domains (eg are you both search engines or they´re a book shop and your a hairdressers), are you targeting the same geographical area or not, are you using the same branding or not etc etc etc If its an international trademark and your using it in your domain your highly likely to get lawyers letters but just because someone sues you doesnt mean they will win.
The OP asked about two famous marks. The answer is a simple "no". Changing the .tld get around infringement. Adding words, phonetic, or misspellings to a TM is still likely going to be infringement i.e. perfumebay vs. ebay or microsoft vs. mikerowesoft (and Mike Rowe was his real name). "Dictionary" words are trademarked all the time. Usage is the key. Descriptive terms are generally not able to be trademarked for their common usage unless the term has acquired a secondary meaning i.e. "Bank of America" and "Vision Center". Famous marks and coined terms can have even broader protection. Trademark law has a lot of grey areas and you should always consult with an IP attorney for specific names and a comprehensive TM search. 99% of people who ask TM questions on DP about famous marks are attempting to ride the goodwill of the TM holder. That is clearly TM infringement and "no you can't do it" is going to be the right answer.
I was not stating that dictionary words are not trademarked however, its easier to argue your use of dictionary words than made up words if you do decide to use a trademark, our local green grocers has had several attempts against them for being called Apples which they have successfully defended. I think they would have struggled more if they´d called themselves Google