To start the beginning

of a?

To be simplified

by a mere?

A way to represent me

is a laugh replaced by you.

But all these clues are irrelevant

What (credit to Deusovi, I'm just addressing the clues)

To start the beginning

of a?

If you let the ? represent the word question, the sentence says "To start the beginning of a question" which the word "what" often does.

To be simplified

by a mere?

In text chat, "?" can mean the same thing as asking "what?"

A way to represent me

is a laugh replaced by you.

If you replace "ha" (a laugh) with "u" (you), then you have phonetically the same word, and "wut" is sometimes used instead of "what" on the internet.