All or nothing
The trend of having to attach your name to everything online is pretty sucky. Example services: Facebook and Google Plus.
It can stop people from trying things, asking questions, and expressing themselves due to fear of reprisal and permanent record.
If I enter into conversation with a stranger, I don’t need to reveal any of my personal information for that interaction to take place, and nor do they. If a rapport it built up we may choose to share some of it, if we get along really well that might include our contact details. In a lot of cases it’ll likely just be a first name, which may be forgotten shortly after.
Sometimes you might have a disagreement with someone. It could be over music tastes, some matter in politics, or maybe they just thought you looked at them funny. What if that someone took serious offense and wished to take it further?
Imagine that they had your full name, a picture of you, a transcript of all your interactions and a direct means to get in contact with you. On many online services this person could be a complete stranger but they would most likely have access to this and maybe more (e.g. location data of that Starbucks you like to frequent).
For this to occur offline someone would likely have to go to considerable lengths to get even a snippet of this information.
Facebook and Google Plus have privacy options, but at the very least the price of admission is usually a full name, which with a little Google fu can turn up all sorts of information. This wasn’t really possible with things like pseudo names, not unless you the user chose to reveal more.
I’ve gone a little to the extreme here, but at some point in your life you’ve potentially offended someone, or they’ve offended you, without maybe even being aware of it. In some cases people may wish retaliate in some manner.
There are plenty of examples from the last decade of people who have issues related to this (look up cyberstalking and such). The ability to move on and forget is becoming close to impossible.