Initially I thought about the expression, breaking the ice; although it's usually used in those embarrassing situations where nobody knows anybody and a deathly silence ensues, a friendly question as an opener can certainly be used as a pretext for a conversation or exchange of information.
It's secondary meaning as defined by The Free Dictionary is:
Break the ice idiom
2. Fig. to initiate social interchanges and conversation; to get something started.
It's hard to break the ice at formal events.
A remark used as an excuse to initiate a conversation:
My store of conversational openers seems thoroughly inadequate to the task.
Sitting down beside him, Brenna wracked her brain for a conversation opener.
A conversation opener is an introduction used to begin a conversation. They are frequently the subject of guides and seminars on how to make friends and/or meet people. Different situations may call for different openers [...]
An opener often takes the form of an open-ended question, which can lead to further comments or conversation as well as creating topics for future conversations (e.g. "How's your mandrill doing?").
A closed-ended question (e.g. "Nice weather today, isn't it?") is regarded as potentially less effective because it can be answered with a simple "Mm-hmm," which is essentially a conversational dead end, requiring the initiater of the conversation to start from scratch.
Consequently, according to Wikipedia, the question "Remember yesterday when we talked about [X]?" would be termed as a close-ended question. As the OP rightly observed when speaking with friends a simple "yes" or "no" response is not expected, but a question is just one of many informal "tactics" that people employ everyday in order to introduce a topic or start a conversation.