Let's say someone sent me a link to an article that discussed a certain topic and I liked that topic so much I couldn't get enough of it and I just kept reading one article after another until I was hooked.
That link, for example, was also the reason I bumped into other interesting things that I might have never seen if it wasn't for it.
Is there an idiom for this, similar to:
"This made me step into a new world"?
I think the idiom you are looking for is "it opened up a whole new world to me".
"Made me step into..." sounds like you were forced to do something. In fact they just "opened up", or 'revealed' something which you had not seen before and which appealed to you.
If you want to emphasize the interesting things you've learned, and how glad you are to have learned them, then I'd agree with @Astralbee's answer.
If you want to emphasize the amount of time you spent reading, or the amount of articles you read, or the large number of interesting facts you've learned, than I would personally use the idiom "fell down the rabbit hole" or "led me down a rabbit hole".
For example, "I went online to find a good sushi restaurant, but that just led me down a rabbit hole of Japanese culinary history."
When you're exposed to a new idea that broadens your understanding, we often say:
"It opened my eyes."
As in, you've been walking around blind without even knowing it- And now the world is so much bigger than you thought.
