[analogmemory]

If I'm feeling snarky, I'll say

  "Looks like you've already asked a question there ;)"

A nice way to help folks is to say to them after the exchange,

  "Feel free to ask your question when you ping me so we don't have to do the hello/hi exchange"

[satyrnein]

It might work, but I'm not sure the typical person would interpret that as "nice" or "help[ful]"...