Suppose I use a certain title on my website which is currently not a trademark. Some other websites use it too. 1) if someone were to register this title as TM can I keep using it on my website because it was used there before TM was registered or filed for? 2) Is it expensive to register a TM? 3) Would the fact that other websites use this title prevent me from registering a TM?
Trademarks do not need to be registered. If another website asserts trademark rights, then it would come down to who used it first (first usage) not the filing date (if they were using it before they filed). Figure at least $1,000 to go through the trademark process with an attorney. It can get a lot more expensive if the mark is contested. 3) First usage establishes rights. It wouldn't stop you from filing a trademark, however, they could contest your filing and take legal action to stop you from using it. Trademarks do not become uncontestable for approximately 6 years after filing. There is a 5 year period from publication for attempt to cancel a mark.