Ideas on Internet-based services

Since internet plays such a significant role in our lives - I got to wonder, what Internet-based services do you find the most valuable / use most often or are most satisfied to have? And which of them do you think are the most meaningless?

And question number 3 - if someone asks, what down-to-earth Internet-based service would YOU suggest could be launched to make ones life better? (does not matter if your idea has already been used by anyone - no need to check)

If you just happen to have any thoughts around this, no matter how crazy or commonplace they might appear, share them!
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My own thoughts around this:
1 - the most valuable service: internet security solution where you do not need to install any software locally (antivirus, antispy, spam filter, well, everything that assures your security while on-line). Your line is just protected all the time - nothing to install, update, no pop-ups to live with.
2 - meaningless I think are fridges ordering milk themselves. Does anyone actually use this feature?
3 - what could be launched: I would kind of fancy being able to know when my kid gets home. Like, I am at work, and at some time an e-mail arrives with a picture of someone just having opened my door - I know the kid's home, plus I know the door has been opened and this was not a burglar