Some members have the exact ad-profile photo.

[LTU_btc]

I don't see nothing strange in OP's question. When I just joined Bitcointalk, I had similar questions why multiple users have same signatures and avatars. I thought they promote personal business, but then why multiple users are doing it. Then I thought it may be ref links in signature, so I checked - it's not.
I saw posts about signature campaigns, but I couldn't relate to this and thought WTF it is.

And who conducts these marriages ? The Signature Campaign Managers 

They are priests of Bitcointalk .

[LFC_Bitcoin]

Or joniboini and Lauda

They just got married 

It was a lovely service, LoyceV was a great pastor & Foxpup, Vod & The Pharmacist were beautiful bridesmaids.
TMAN didn’t make the service due to getting far too drunk on the way to the Church.