How to recognise bitcoin addresses

[Tyger]

Yes i know you can't link a address to a person, but how do site's like blockchain.info know that they belong to exchanges or Satoshidice or whatever?
Is this just public information that they gathered?

[odolvlobo]

Yes, public information.

For example, in the past Blockchain.info has scraped Bitcointalk user signatures for addresses, and associated user names with those addresses. Like this: https://blockchain.info/address/1NhMCm8fYaHmVanKx33yhh1gfVW1DMBUjZ
I asked them to remove the link to me and they refused.

[socks435]

Is it possible to know if those address have their own names or tag added or they are vanitygen generated..
Like bitmixer they have their wallet address 1BitmixerEiyyp3eTLaCpgBbhYERs48qza
or tag the same as this address https://blockchain.info/address/1FTziwutvwSG58XCc7ncnthiPg8NCBh69L
from second trade..

[MingLee]

Yes i know you can't link a address to a person, but how do site's like blockchain.info know that they belong to exchanges or Satoshidice or whatever?
Is this just public information that they gathered?

Most of the time the only information that can be attached to an address is public information, so there's a high chance that any time you see any sort of pairing between an address and some sort of website it is public information next to 100% of the time, unless someone else willfully makes the connection.
It's likely never going to be paired to you.