Facebook is poking around into what users of its recently released Poke iPhone application think, tapping research firm Ethnio to conduct phone interviews via Skype or GoToMeeting.

Sister blog Inside Facebook reported that Facebook and Ethnio placed ads on the social network seeking respondents, who must first answer short questionnaires, with those selected to proceed rewarded with $75 Amazon gift cards. Participants must have webcams, as well.

Poke soared out of the gate after its Dec. 21 launch, reaching the top spot in Apple’s App Store, before sliding, and Inside Facebook reported that Poke now sits at No. 343.

Readers: What do you think Facebook is trying to find out about Poke and Poke users?

Screen grab courtesy of Inside Facebook.