Table 5 A Characteristics of the five most central actors across layers on forum A. B Characteristics of the five most central actors across layers on forum B.

ID	No. networks most central	In-degrees			Out-degrees			Roles				No. public posts	No. public posts with link	No. private messages	No. private messages with link
ID	No. networks most central	Public replies	Private messaging	Flat-tened	Public replies	Private messaging	Flat-tened	Adminis-trator	Mode-rator	VIP	MVP	No. public posts	No. public posts with link	No. private messages	No. private messages with link
A
19406	6	1	1	1	1	1	1	1	1	1	1	4041	910	1646	232
32890	4	0	1	0	1	1	1	0	1	0	1	2181	935	1327	695
11615	3	1	1	1	0	0	0	0	0	0	0	312	146	274	31
6500	3	0	1	0	0	1	1	0	0	0	1	955	567	575	45
50229	3	0	0	0	1	1	1	0	1	0	1	2561	376	609	252
23406	2	1	0	1	0	0	0	0	0	0	1	3492	2835	283	117
13502	2	1	0	1	0	0	0	0	0	0	1	758	514	240	37
93933	2	1	0	1	1	0	0	0	0	0	1	1445	366	111	22
1	2	0	1	0	0	1	0	1	0	0	0	1118	161	2433	240
6306	2	0	0	0	1	0	1	0	1	0	0	3814	397	1776	223
												Geometric mean (SD)
												2.31 (3.01)	2.13 (3.13)	1.91 (2.69)	1.76 (2.51)
												Median (MAD)
												2.00 (1.00)	1.00 (0.00)	1.00 (0.00)	1.00 (0.00)

ID	No. networks most central	In-degrees			Out-degrees			Roles			No. public posts	No. public posts with links	No. private messages	No. private messages with link
ID	No. networks most central	Public replies	Private messaging	Flat-tened	Public replies	Private messaging	Flat-tened	Adminis-trator	Mode-rator	“Reup doctor”	No. public posts	No. public posts with links	No. private messages	No. private messages with link
B
2	6	1	1	1	1	1	1	1	0	0	12,266	1844	2926	356
62260	2	0	1	0	0	1	0	0	0	0	230	27	757	96
85	2	0	1	0	0	1	0	0	1	0	6451	2625	1845	500
118502	2	0	1	0	0	1	0	0	1	0	1652	604	858	355
192	2	0	1	0	0	1	0	0	1	0	4459	2368	624	172
488	2	1	0	1	0	0	0	0	0	1	1870	442	179	37
54754	2	1	0	1	0	0	0	0	0	1	1243	787	39	10
678	2	1	0	1	0	0	0	0	0	0	816	343	86	35
8700	2	0	0	0	1	0	1	0	0	0	2640	794	214	47
72462	2	0	0	0	1	0	1	0	0	0	1567	241	56	12
19025	2	0	0	0	1	0	1	0	0	0	5746	1332	50	1
103	2	0	0	0	1	0	1	0	0	0	1423	89	108	11
3622	1	1	0	0	0	0	0	0	0	0	1778	1115	162	78
5222	1	0	0	1	0	0	0	0	0	0	2846	879	835	131
											Geometric mean (SD)
											3.98 (4.92)	4.31 (6.14)	5.53 (4.30)	3.02 (3.40)
											Median (MAD)
											2.00 (1.00)	2.00 (1.00)	4.00 (3.00)	2.00 (1.00)

Due to the skewed distributions, the last four rows show the geometric mean (excluding zeroes) and the median across all forum members who were active on the respective part of the forum, i.e. contributed at least one public post/reply (with link) or sent at least one private message (with link) for each particular column.

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