Is there any legal problem in using a popular website name as a suffix which is available for registration. For example: Healthyahoo.com or Yogawikipedia.org. Will they sue me? Thanks in advance..
Just because you have not yet been caught does not mean you wont be. ofcourse it is illegal and just asking to be sued.
Yup. Look up domain and trademark infringement. You won't necessarily be sued, but you might receive a C&D notice asking (or demanding) you give the domain name to them or else. If you especially use a famous one like those you mentioned above, you'll surely get their attention. Up to you.
You may well get a C&D notice irrespective of what your doing with them. The likelihood of their request being enforcable will depend on the actual brand name (eg is it a dictionary word), what the topic of the site is -v- what the brands areas of activity are, any similarity of branding and which country you operate and host from. If your looking to make money from their brand or make it look as something to do with their brand you will probably have issues unless it is simple "commentry" - some countries do allow fair use for commentry of trademarks. If your wanting to have "InsureTheGAP.com" and offer GAP insurance then your unlikely to run into problems with the clothing brand GAP (but they may offer to buy the domain anyway)
This is a legal question. And an important, integral decision for the future well-being of your company. Get legal advice dude. I'm no lawyer but based on what you said above, I wouldn't go forward without seeking legal advice. Seriously.
A rather blanket statement. It depends on the specific case, and issues such as do they have a trademark in your jurisdiction. Andrew, of course, is correct. Seek professional legal advice, not forum chat.
If I started a site called Amazonfinds.com it could either be illegal or legal. Legal: Amazon finds - If it was a blog about the actual amazon not the company. I would capture beautiful images of the amazon. I could be sued, but they'd have no possible way of winning unless they bought the judge. Illegal: using it to relate to their company. Amazon sells cd's? I'm not sure what they sell only been there once and I know it's not about the actual amazon. I wouldn't call it that then show cd's.