Memorizing all national flags is probably useless; I wouldn't worry about that.
Often I can't focus on thing in detail only skimming whole articles.
However, this is a serious problem. Please, let's not deny it! Even if Google gives you a relevant and correct article anytime you ask a question (which is far from guaranteed), if you are not able to process the article, you are becoming effectively stupid. Yeah, you can find anything; you just can't understand it!
This may seem exaggerated, but as a teacher I have seen it recently with many high-school students, and it's scary. The kids can use Google to find anything; then they can print the answer and bring it to school as their homework. But they are not able to describe the content of the article using their own words! They are able to get the answer from the other side of the planet in front of their eyes; it just cannot enter their brains. They will read it, and read it again, but that's all they can do with it; there is very low reading comprehension. Their parents are usually impressed by their ability to find various texts; but the problem is that despite having all knowledge of the planet at their fingertips, the knowledge remains arcane.
(Then in the later age we see various programmer-wannabes building their code from PHP and JavaScript snippets found online. If a variable name is changed, they can pattern-match it, but they don't truly understand what they wrote. If a greater change is needed, they start asking other people to do their homework for them. It's the same "question - answer - no comprehension" pattern over again.)
It is sane to be concerned when "googling" becomes a substitute not only for long-term memory, but also for understanding and thinking.
So, what is the solution? I don't have a full answer, but this seems to help:
1) Avoid stupid texts, and only read smart texts. Which could mean that you will regularly read only two or three websites and mostly avoid the rest of the internet. Sometimes it means that you will read the articles only, and intentionally skip the discussions below them. Be suspicious about too many too short text pieces.
2) Read something interesting and then discuss it with someone offline. This makes you practice your memory and text comprehension.
3) At the end of the day, try to remember all web pages you have read during the day. How many of them do you remember the topic of? How many of them could you summarize in one paragraph? This gives you some feedback on how much you are wasting your time. (I mean: if you don't remember it, or if there is nothing to remember, why waste your time reading it? Are you aware that you have some limited time here, and then you die?) Then, for a reality check, open your browser's history and see how many web pages have you really read during the day.