does anyone have any idea what programming language is used for these softwares.

If it's windows based it's probably C# or C++. That said, it doesn't really matter what language they are using as it can be accomplished with any language that has SOCKS or TCP/IP support (which most do).

NicheShark appears to be using PHP on the backend, and JavaScript on the front end, which is a really common combination.

PHP has a bunch of features that make it ideal for doing this kind of work (though lots of other languages would be fine as well). Most of these kinds of tools will use cURL to connect to other Websites, and a database to store and index keywords. These keywords in turn allow for searches to be performed, etc. For backlink checking, it is really a matter of having a list of target pages, and then searching for those as links in the pages that are checked.

Sophisticated systems will cache the sites that they monitor, to save on bandwidth, increase speed, and prevent sites from blocking them.

The key to making something like this work is to have a marketer that understands the process really well (as in, they could teach a 5 year old to do it in a "paint by numbers" kind of way), who then explains it to a developer (or small team) to implement it.

Not a project for the faint of heart.

According to me javaScript is much easier than C or C++

my brother told c++ is able to make those kinda softwares
regards

C is the language for these things

i use C# and .NET 4.0 for my Places Scout software (link in sig) that does tons of automated web scraping...its the easiest for me to get alot done in the shortest time possible...if you go the web server route then you can use either C# / ASP.NET or PHP...i'd prefer ASP.NET but PHP isn't that bad...just not a rapid development language IMO..i get a lot done a lot quicker in C#.