Meaning of “What else is new”

Question

I sent an email to my colleague for any questions he had, he could feel free to ask me.

This is the reply from him:

Will do, just got sidetracked for a bit here… what else is new. =)

Should I understand "What else is new" as a question or something else? It happens to seem an informal way of saying something but I couldn't really understand the informal meaning. I know what it says literally though.

TheFreeDictionary.com defines it:

Inf. This isn't new. It has happened before; Not this again.

But personally, I couldn't fit its definition in my colleague's sentence.

Answer 1

It is an ironic idiom meaning that something happens frequently. In this sentence, it means that he is always getting sidetracked.