Katy is a really inteligent person.
She gives love to any fan when they talk to her in the real life. I think internet is not so important for show somethings.
For example Justin Bieber and Lady Gaga follow fans but they don't talk or tweet to them 'cause they are so many.
If Katy follows 1,000 2,000 or more fans, the others would become jealous and the worldwide katycat twitter would be just fights between fans.
Katy knows how important are her fans and she shows her love to us in her own way ;D