I currently have 13,229 bookmarks in Pinboard.in. They are all cross referenced with multiple useful tags and I add maybe 3+ every day.
Google is a poor substitute because it gives me pages of results for what I need and they may or may not be any good. I may have to search again. I may have to click through 4 or five pages before i find one that's useful even though i've been to a useful one before.
Searching in my bookmarks gives me ones that are KNOWN useful, AND because of Pinboard's archival feature they are still available even after the site has disappeared.
I bookmark things _I_ find useful and things I think will be likely be useful to the people in my circles. Then when a friend says "hey is there a good tool for x?" I can say "yes, and here's a link to it" even if i don't use that tool. Or, i can link them to full pages of useful bookmarks on a topic.
So yeah, I have thousands of curated links of _useful_ things and pieces of information that are on the internet or _were_ on the internet. I use it daily. I share links with others regularly. I'm constantly thankful when i can read the content of that blog post I bookmarked that described X better than anything currently out there... but no longer exists on the internet. It's also great for research. I can make a new tag for some topic I'm gathering info on (maybe competitors for a future project) and when i am ready to start processing that info i have a whole list of easily accessible links to go through.
re "is it a service people need anymore?" Note that the reason the thing that started off this discussion exists is because enough people are paying him money to use Pinboard.in that he was able to spend unknown thousands of dollars on Delicious for the SOLE purpose of shuttering it and putting it in read-only mode. He probably got some users who transferred their accounts to Pinboard.in out of the deal, but that wasn't his primary goal by all accounts.