How challenge it is to choose an online username and a domain name

Choosing a nickname for a website to sign up into a social network site it's somewhat a challenge for me and I believe it is for so many people as well.  I usually spend sometimes to figure out which nickname to go by when sign up for an online community because the ones I wish to have usually not available, and it goes the same way when it comes to choose a domain name.  It seems that in the future all the new websites will have longer charater domain names,  for there will be no domain name shorter then 7 alphanumeric character available to choose from because as many many more websites will definitely be created..

After all, I think it is very very challenging to find a suitable username and a favorite domain name for a website.