Table 1.

Description of Variables.

Variable	Measure item	Description
Dependent variable
Public engagement	Public engagement breadth (PEB)	The sum of the number of reposts, comments, and likes of each post.
	Public engagement depth (PED)	The relevance between the content of comments below each post and the content of each post.
Independent variables
Information timeliness	Information retrospectiveness (Retro)	The relevance between a post at time t and all posts at time t-1.
	Information immediateness (Imme)	The relevance between a post at time t and the other posts at time t.
	Information prospectiveness (Prosp)	The relevance between a post at time t and all posts at time t + 1.
Moderate variable
Information richness	Richness	The richness level of each post.
Control variables
Followers	Fans	The number of followers of the poster.
URL	Url	Whether the post contains URL(s).
Length	Length	The content length of each post.
Views	Views	The number of views of each post.