What is it called when you search for something on the internet and end up looking for other and it goes in endless meander? [duplicate]

Tab-surfing

From wikipedia:

Tab-surfing, also more accurately known as 'Branching' is a type of link-surfing in which, rather than click directly through to the next web page, the link is opened as a new window or new Tab. This method is used by people wishing to read as much information as possible on a variety of subjects which may or may not be related.

The parent article is about Link-surfing:

Link surfing is the process of starting on one article on a website and clicking on various hyperlinks to eventually finish on a different (pre-determined) article.

There are all sorts of web browsing details here.

Go down a rabbit hole

To enter into a situation or begin a process or journey that is particularly strange, problematic, difficult, complex, or chaotic, especially one that becomes increasingly so as it develops or unfolds.

"Owning your own business is a huge responsibility that not everyone is prepared for. Are you sure you're ready to go down the rabbit hole?"

"I've stayed away from drugs and alcohol since coming to college. I have an addictive personality, so I decided to just avoid going down that rabbit hole altogether."

"Overhauling the current tax legislation is a rabbit hole I don't think this administration should go down at this point."

It's probably a reference to Alice's Adventures In Wonderland, (often referred to as Alice In Wonderland) which starts off with the titular heroine following a strange looking rabbit down a hole, after which all sorts of strange events unfold.

In addition to the other answers, a specific example of the phenomenon when applied to wiki pages (such as Wikipedia, or TV Tropes) is often referred to as a wiki walk.

As Urban Dictionary defines it:

wiki walk

Randomly following Wikipedia links and reading articles, which ends up wasting a lot of time.

The longer the walk, the more unrelated the articles become.

XKCD calls this a "tab explosion".