Q: What is openalias? How does it work?
A: openalias is Monero's aliasing system. It is meant to make it simpler to send moneroj to an address, by applying a label (itself using DNS) to an address. Using DNS prevents landgrabing (of course, landgrabing DNS itself is still an issue).
For instance, if you want to send moneroj to support the development of Monero, you can either send to the dev fund address
or the much simpler to memorise alias:
Of course, before sending to an alias, the said alias must have been created - see the openalias website for instructions.