You can now surf the web for sources with NotebookLM
Google's NotebookLM has added a source search feature that lets you expand your notebooks with new information from the internet.

If you’re a NotebookLM user, you can now find extra sources for your notebooks from the internet just by describing what you want. The feature started rolling on Wednesday and Google expects everyone to have access in about a week.
Until now, creating a new notebook meant manually adding sources yourself (as many as 50 for free users and 300 for paid subscribers). This meant uploading PDFs, websites, Google Docs, YouTube URLs, and other file types to create your library of information.
You can still add files manually now but the new Discover feature lets you supplement your existing sources with new information from the web. Type in the topic you’re interested in and NotebookLM will gather hundreds of potential sources, analyze them for relevance, and return up to 10 recommendations for you, each with a quick summary of its contents.

From there, you can add the suggested sources to your notebook with one click and use them just like you would use a manual source. For instance, you can ask NotebookLM’s AI model natural language questions about your sources, and choose which sources the model should use or not use to answer your questions.
The idea is that NotebookLM will only use information from your notebook to create its responses (rather than pulling random facts from the internet), and it will include citations to show where the information came from, allowing you to jump to that section of the source to read more.
As you’re researching, you can create notes from the responses the model gives you or write up your own notes. You can also add your notes as an additional source so the model can use the information in future research sessions.
Other popular features include the Audio Overviews which are now also available on Gemini, and the new Mind Maps feature that launched a few weeks ago.
NotebookLM will only add the sources you approve and you’ll always be able to see the full original sources, choose when to include them, see citations when the model uses them, and delete them later if you don’t like them. This should make it easy to stay on top of your notebooks and weed out any bad information that might sneak into them.