The parameter handling allows you to tell Google which parameters in the query string Google can ignore so it cuts down on duplicate content issues. For instance many sites used to include a session ID in the query string (ie '?sessionID=123213213') so they could track a user and personalize a page for them. This session ID could create duplicate content issues since both pages (ones with and ones without the session ID in the query string) would typically show the same content. By letting Google know which parameters in the query string they can ignore you make the job easier for Google to determine which and which is not a unique page. If you told Google to ignore the session ID in the query string, then Google would know that 'www.example.com/index.html' is the same page as 'www.example.com/index.html?sessionID=123324324'. If you did not tell Google to ignore the sessionID in the query string and you were not using a canonical tag, then Google would view both of them as unique URLs, even though they both display the same content, and you could have duplicate content issues. Here is the official Google explanation of this function: http://googlewebmastercentral.blogspot.com/2009/10/new-parameter-handling-tool-helps-with.html
Ok for example I have this link http://wegotthiscovered.com/movies/...iscovered/NCkI+(We+Got+This+Covered+RSS+Feed) Now normally I should tell Google to ignore the parameter utm_source right? But if you look, the canonical on that page is to the correct link, http://wegotthiscovered.com/movies/idris-elba-wanted-pacific-rim/, so do I still need to tell google to ignore that parameter
I would not worry about adding it as long as you are using the canonical tag. I have never used the parameter exclusion functionality, I just use the canonical tag. This is from Google's website about when to use which one: When do I use parameter handling vs rel="canonical"? rel="canonical" is a great tool to manage duplicate content issues, and has had huge adoption. The differences between the two options are: rel="canonical" has to be put on each page, whereas parameter handling is set at the host level rel="canonical" is respected by many search engines, whereas parameter handling suggestions are only provided to Google Use which option works best for you; it's fine to use both if you want to be very thorough.
I need a help here. If there are some page urls abc.com/xyz-brand/visit.php generated for the tracking the visits to the brand xyz but it does not exixt physically and is generated on click and goes to xyz.com. Now the problem is what should i do if these visit.php pages appear in the list of site:abc.com, i can not block them in robots.txt file because i need them to track how many visits i send to xyz.com through google analytics. Is it a problem if i leave them like that only and do not do anything as physical copy do not exisit and it is just onclick url generation and redirection.