"Other uses of the progressive aspect It may be used especially following the auxiliary will or shall with the special implication that the action will take place 'as a matter of course' in the future: I'll be seeing you next week. Note: 'The 'matter-of-course' implication of will or shall with the progressive is also found with other modal auxiliaries, and possibly also with the past progressive in conversational contexts; eg: I was talking to Anne, and she was telling me that the job is still vacant. In contrast to the simple past talked and told, the progressive here suggests a casual chat rather than a purposeful discussion."

My question is: what's the "matter of course" implication in ' I was talking to Anne, and she was telling me ..."; and why ING form is more conversational in contrast to simple form? I can't see any link between "will be ING" and past progressive. could you help me? thank you.

The "matter of couse implication" in "I was talking..." simply means that she hadn't made it a point to speak with Ann about the vacancy: It just came up in the conversation.  The reason the -ing form is more conversational is because that is how it's been regularly used in the context of speech, and how most people would interpret it. 

kimlrobles

“I can't believe I just wrote the reason is because! oops”

(Twenty lashes with a wet noodle.)

Will do better next time.

Will do better next time.

Will do better next time.

...

CJ